1. What is the units digit of the number $2015^{2}+2015^{0}+2015^{1}+2015^{5}$ ?
A 1
B 5
C 6
D 7
1. C The units digits of $2015^{2}, 2015^{0}, 2015^{1}, 2015^{5}$ are $5,1,5,5$, which add to 16 . Thus, the units digit of the sum is 6 .