Ryiaz claims it is impossible to prove that a rational number multiplied by an irrational number gives an irrational product. How can you prove this?

A. He's correct; it is impossible to prove in any way.
B. By using a proof by contradiction to show multiplication is a closed operation for rational numbers.
C. By creating a proof that shows directly how multiplying a rational and irrational number leads to an irrational answer.
D. By choosing random numbers to plug into multiplication problems until he's convinced.