Which of the following numbers is not prime? (Hint: avoid actually computing these numbers.)	Choose the most appropriate option:
A) 6!-1	B) 6!+21	C) 6!+41	D) 7!-1	E) 7!+11
Notice that we can factor out 3 out of 6!+21 --&gt; 6!+21=3*(2*4*5*6+7), which means that this number is not a prime.   Answer: 6!+21
<result>B</result>
Which of the following numbers is not prime? (Hint: avoid actually computing these numbers.)