While calculating time complexity of an algorithm, the designer concerns himself/herself primarily with the run time and not the compile time. Why?

Option 1 : Run time is always more than compile time.

Option 2 : Compile time is always more than run time.

Option 3 : Compile time is a function of run time.

Option 4 : A program needs to be compiled once but can be run several times

Answer: Option 4