What is the unit digit in (4137)754?

Question:
What is the unit digit in (4137)754?

[A].

1

[B].

3

[C].

7

[D].

9

Answer: Option D

Explanation:

Unit digit in (4137)754 = Unit digit in {[(4137)4]188 x (4137)2}

=Unit digit in { 292915317923361 x 17114769 }

= (1 x 9) = 9