Concept: The question tests on the basics of Counting
The number of ways of arranging n distinct objects, when repetition is not allowed = n!
For the number to be even, the last digit should be either 4 or 8, so 2 ways of filling the last digit.
The remaining 3 digits can be arranged in 3! = 6 ways
Total such numbers = 6 * 2 = 12