The correct answer is option 4, which states that all the pairs given are correctly matched.

1. Pinaka: It is a multi-barrel rocket launcher system developed by India. It is used for artillery fire, providing rapid and precise target engagement. The Pinaka system can launch multiple rockets simultaneously, making it an effective weapon for destroying targets over a large area.

2. Nag: It is indeed an anti-tank missile system developed by India. The Nag missile is designed to take out enemy tanks, armored vehicles, and other heavily fortified targets. It is a fire-and-forget missile, meaning it can lock onto its target and hit it without requiring further guidance.

3. Lakshya: This is also correctly matched. Lakshya is an unmanned aerial vehicle (UAV) developed by India. It is used for target acquisition, artillery fire correction, and aerial reconnaissance. The Lakshya UAV can be remotely controlled or flown autonomously.

Therefore, the given pairs are all correctly matched, and option 4 is the correct answer.