The correct option is option 3: 1, 3, and 4 only.

Let`s dissect each statement to understand why.

Statement 1: It is a single stage missile.

This means that Prahar missile is composed of a single propulsion unit, which simplifies its design and operation.

Statement 2: Its striking range is about 500 km.

This statement is not mentioned in the given information but it doesn`t affect the correct answer.

Statement 3: It is fueled by solid propellants.

This means that the Prahar missile uses solid propellants instead of liquid or hybrid propellants. Solid propellants are typically easier to handle and store.

Statement 4: Several Prahar missiles can be fired in one salvo.

This means that multiple Prahar missiles can be fired simultaneously or in quick succession. This capability enables a higher volume of firepower to be deployed in a shorter period.

In conclusion, the correct statements are 1, 3, and 4.