The product A of the first 10 prime numbers is closest to which of the following?  Choose the most appropriate option:
A) 6.5 x 10^7
B) 6.5 x 10^8
C) 6.5 x 10^9
D) 6.5 x 10^10
E) 6.5 x 10^11
The first 10 primes are: 2, 3, 5, 7, 11, 13, 17, 19, 23, and 29.   So, we need to find approximate value of 2*3*5*7*11*13*17*19*23*29.   # of different approximations are possible. For example:    2*5= 
<gadget id="calculator"> 2*5</gadget>
<output>10</output>
10   3*17=~50 (actually more than 50);   7*13=~100 (actually less than 100);   11*19=~200 (actually more than 200)   23*29= 
<gadget id="calculator">23*29</gadget>
<output>667</output>
667=A   2*3*5*7*11*13*17*19=~10*50*100*200*667=10^7*667=6.67*10^9.   Answer: 6.5 x 10^9.
<result>C</result>
The product A of the first 10 prime numbers is closest to which of the following?