The correct answer is option 3: KEVLAR. Kevlar is a polymeric material that is commonly used for making bulletproof jackets. Kevlar is a high-strength synthetic fiber that is lightweight and known for its exceptional strength and resistance to impact. It is made from poly-paraphenylene terephthalamide, a type of aromatic polyamide.

Nylon 6,6 (option 1) is a strong and durable synthetic polymer, but it is not typically used for making bulletproof jackets. It is commonly used in textiles, ropes, and engineering plastics.

Rayon (option 2) is a semi-synthetic fiber made from natural cellulose, but it does not possess the necessary strength and ballistic resistance for making bulletproof jackets.

Dacron (option 4) is a brand name for polyester, which is a synthetic polymer. While polyester has some strength and durability, it is not commonly used for making bulletproof jackets.

Therefore, the correct answer is option 3: KEVLAR, as it is specifically designed and widely used for its high strength and ballistic resistance, making it suitable for bulletproof jackets.