Answer:
Program counter:In computer processor the program counter is a register that holds the address of the instruction being executed currently.They are also known as instruction pointer (IP) .When instruction are fetched then program counter increases and hold the the address of the next instruction by increasing and storing her value by 1.
The purpose of program counter is " to keep the track of currently execution"
The address of the next instruction is hold by program counter in the main program.
The program and data means both data and instruction stored in memory.