A number x is multiplied by 5, and this product is then divided by 7. If the positive square root of the result of these two operations equals x, what is the value of x if x≠0 ?  Choose the correct choice from the following choices: A) 25 / 9 B) 9 / 5 C) 5 / 7 D) 3 / 5 E) 9 / 25

Rationale: "sqrt ( 5 x / 7 ) to be perfect square x has to 5 / 7 ans : c"
Answer: C