Number properties

[ashforgmat]

130) Positive integer k has exactly 2 positive prime factors, 3 and 7. If k has a total of 6 positive factors, including 1 and k, what is the value of k?
a. 3^2 is a factor of k
b. 7^2 is not a factor of k


Please can someone look into this ...i thought the answer was E but its given as D !!!

[liferocks]

if a number is of the form m^p*n^q where m and n are prime then number of factors is (p+1)(q+1)


From 1

3^2 is one of the factor and 7^p is another..hence 3*(p+1)=6 or p=1
so the number is 3^2*7=63..sufficient

From 2 ..similar to the argument for 1..k=3*7^2=147..sufficient

Ans option D