Default compiler used in keil for 8051 microcontrollers

Hello all,
I wanted to know which is the default compiler used in keil for 8051 (example. P89V51RD2) controllers. Can we change the compiler? There are some other names like realview gcc in keil when we create a project we can see it. So got this doubt. Can anybody help regarding this. Thanks in advance

You may have misunderstood some of the terms used.

A compiler is a general term for any program that
turns lines of C code into code the micro can use.

Keil is the name of the company that makes a popular compiler.

There are other compilers for the 8051, some you pay for, some are free.
Use which ever you like and can afford

@ExperimenterUK

Thanks a lot for correcting my misconception about compilers. 😊