The smallest value of n, for which 2n + 1 is not a prime number is Choose one:
A) 3
B) 4
C) 5
D) 6
E) 7
Sol.   = (2 × 1 + 1) = 3,   = (2 × 3 + 1) = 7,   = (2 × 4 + 1) = 9, which is not prime.   Therefore n = 4.   Answer 4
<result>B</result>
The smallest value of n, for which 2n + 1 is not a prime number is