Visual aids in which the messages are written and presented step by step to the audience is :

Question

Accepted Answer

The correct option is 4:
Flash Cards are a specific type of visual aid that consists of a set of small cards, each containing a single piece of information, a question, an image, or a step in a process. The reason they fit the description is their inherent design for sequential unveiling. The presenter holds the stack of cards and physically reveals them to the audience one by one, allowing for a controlled, step-by-step presentation of the message. This method is exceptionally valuable when the topic is linear—such as teaching the steps in a recipe, a sequence of historical events, a chemical reaction process, or building up a complex story. By showing one card at a time, the instructor can ensure that the audience fully grasps the current point before moving on to the next, maintaining focus and engagement and preventing information overload. They also offer great flexibility for review, reordering the sequence, or reinforcing concepts through quick repetition, making them an ideal tool for effective step-by-step communication.

The incorrect option is 1:
A Bulletin Board is essentially a passive display area, typically made of cork or soft material, used for pinning up various notices, announcements, and miscellaneous educational materials. Its purpose is to present a collection of information, often unrelated or broadly grouped by theme, simultaneously and continuously for an extended period. The audience is expected to approach the board and read the messages at their own pace. There is no active control by a presenter to reveal the messages sequentially, and all written content is visible at once, which disqualifies it from being an aid for a step-by-step presentation.

The incorrect option is 2:
A Poster is defined by its role as a single-frame, non-projected visual aid designed to convey a striking and memorable message, often for publicity or general awareness. The message is holistic and all elements—text, images, and colour—are organized on one sheet to be absorbed quickly. Since a Poster is always viewed in its entirety, it cannot be used to present a message or a series of facts sequentially, as the requirement for "step by step" implies that one message is presented, concluded, and then the next is introduced.

The incorrect option is 3:
A Chart is a large visual display used to present facts, figures, and relationships in a systematic, often diagrammatic form, such as a bar chart, pie chart, or a simple picture chart. While a specific type like a flow chart or a strip chart can show a sequence, the physical item itself is generally displayed on a single surface, revealing the entire structure and all the steps at the same time. The instructor must manually point out the sequence, but the visual aid's presentation is whole rather than controlled and piece-by-piece. The key distinction is that Charts display the *entire* process at once, whereas Flash Cards are designed to physically *unveil* the steps sequentially to the audience.