The polynomial x3+8 is equal too (x+2)(x2-2x+4

For starters:  Please practice presenting polynomial expressions properly.

x3+8 is equal too (x+2)(x2-2x+4  

should be written as   "x^3 + 8 is equal to (not too)  (x+2)(x^2 - 2x + 4).

You don't share the instructions.  I suspect you are to respond "true" or "false."

It happens that x^3 + 8 equals   x^3 + 2^3, which is the sum of two cubes.

There is a formula for the "sum of two cubes:" 

It is a^3+b^3 = (a^2 - ab + b^2)(a+b).

Therefore, x^3 + 2^3 = (x+2)(x^2 -2x + 2^2), or (x+2)(x^2 - 2x + 4).

The correct answer here is c