What is the unit digit in {(6374)1793 x (625)317 x (341491)}?

Question: What is the unit digit in {(6374)1793 x (625)317 x (341491)}?
[A].

0 

[B].

2

[C].

3

[D].

5

Answer: Option A

Explanation:

Unit digit in (6374)1793 = Unit digit in (4)1793

    = Unit digit in [(42)896 x 4]

    = Unit digit in (6 x 4) = 4

Unit digit in (625)317 = Unit digit in (5)317 = 5

Unit digit in (341)491 = Unit digit in (1)491 = 1

Required digit = Unit digit in (4 x 5 x 1) = 0.