Concept:
Aramid fibers (like Kevlar and Nomex) are high-performance synthetic fibers valued for their extreme thermal and mechanical resistance.
Step 1: Evaluating the Assertion (A):
Aramid fabrics are indeed used extensively in protective clothing (such as firefighter suits and bulletproof vests) due to their heat resistance and durability. Assertion (A) is correct.
Step 2: Evaluating the Reason (R):
While aramids have high strength, they are known for being inherently flame-resistant, not for having "high flammability." High flammability would make a fiber dangerous for protective use. Reason (R) is incorrect.
Step 3: Conclusion:
Since the assertion is true but the reasoning provided is factually wrong regarding flammability, option (3) is the correct choice.