How many even number of four digit number can be formed from the digit 12345 , if reptition is permitted

please explain it because i am in learning stage.
A-24 B-40 C-250 D-124

Four digit number is even if it ends with either2 or 4
Number ending with 2 = 5^3
Number ending with 4 = 5^3
Total even numbers= Number ending with 2 +Number ending with 4 = 5^3+ 5^3= 2 5^3= 2*125=250

Since repetition is allowed, you have

5 choices for the first digit
5 choices for the second digit
5 choices for the third digit
2 choices for the last digit

Multiply 5*5*5*2 and you'll have the answer.