An Assertion (A) and a Reason (R) are given below. Assertion (A): Ventilators…

Concept

Heat can transfer by conduction, convection, or radiation. Conduction is transfer between particles in direct contact within a solid (or between touching bodies), with no bulk movement of material. Convection is the bulk movement of a fluid — air or water — driven by density differences that arise on heating: warmer, less dense fluid rises while cooler, denser fluid sinks to take its place.

Application

In a room, air near a heat source warms up, becomes less dense, and rises toward the ceiling; a ventilator placed near the roof lets this risen warm air escape while cooler air is drawn in lower down — a convection current. This makes Assertion (A) true: ventilators are provided near the roof for exactly this reason. Reason (R) claims conduction takes place better near the roof, but conduction requires direct contact between particles of a medium (or between touching surfaces) and does not explain the upward movement of air at all — it is an entirely different mechanism from what is actually happening here. So R is false.

Cross-check — why each other pairing fails

• “A is false but R is correct” — wrong: vent placement follows an established design principle (A holds), and the cited transfer process doesn't even govern how air moves within a room.

• “Both A and R are correct and R is the appropriate explanation of A” — wrong: the cited transfer process is not what governs how warm air rises and escapes here, so it cannot serve as a valid explanation for the assertion.

• “Both A and R are correct but R is not an appropriate explanation of A” — wrong: the cited process itself does not apply in this context at all, not merely as an unrelated true statement.

So Assertion (A) is true and Reason (R) is false — matching the option that states exactly that.