If a is a positive integer, and if the units digit of a^2 is 4 and the units digit of (a+1)^2 is 1, what is the units digit of (a+2)^2?  Choose the correct choice from the following choices.
A) 0 B) 2 C) 4 D) 6 E) 8
If the units digit of a^2 is 4, then the units digit of a is either 2 or 8.   If the units digit of (a+1)^2 is 1, then the units digit of a+1 is either 1 or 9.   To satisfy both conditions, the units digit of a must be 8.   Then a+2 has the units digit of 0, thus the units digit of (a+2)^2 will be 0.   The answer is 0.
<result>A</result>
If a is a positive integer, and if the units digit of a^2 is 4 and the units digit of (a+1)^2 is 1, what is the units digit of (a+2)^2?