What is the units digit of (147^25)^49 ?  Options
A) 1
B) 3
C) 5
D) 7
E) 9
The units digit of the exponents of 7 repeat in a cycle of four, which is {7,9,3,1}. The number 25 has the form 4n+1 so the units digit is 7 inside the bracket. The exponent 49 has the form 4n+1, so the units digit is 7. The answer is 7.
<result>D</result>
What is the units digit of (147^25)^49 ?