A number x is multiplied by 3, 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 one
A) 25 / 9
B) 3 / 7
C) 5 / 3
D) 3 / 5
E) 9 / 25

Rationale: "sqrt ( 3 x / 7 ) to be perfect square x has to 3 / 7 ans : b"
Answer: B