1+2+2^2+2^3=？	Choose the most appropriate option.
A) (2^3-1)(2^3+1)	B) (2^2-1)(2^2+1)	C) 2^5-1	D) 2^5+1	E) 2^5-2
From 1+2+2^2+2^3=1(2^4-1)/(2-1)=2^4-1=(2^2-1)(2^2+1), the correct answer is (2^2-1)(2^2+1).
<result>B</result>
1+2+2^2+2^3=？