If (7)(x^2) has four different prime factors, at most how many different prime factors does x have? Choose the correct option
A) 1  B) 2  C) 3  D) 4  E) 5
x can have at most 4 prime factors, namely the prime factor 7 plus 3 others.   If x had more than this number of prime factors, then (7)(x^2) would have more than 4 prime factors.   The answer is 4.
<result>D</result>
If (7)(x^2) has four different prime factors, at most how many different prime factors does x have?