Solution:
A. 98: 98 is not a multiple of 8 because when we divide 98 by 8, we get a remainder of 2.

B. 124: 124 is not a multiple of 8 because when we divide 124 by 8, we get a remainder of 4.

C. 27: 27 is not a multiple of 8 because when we divide 27 by 8, we get a remainder of 3.

D. 512: 512 is a multiple of 8 because when we divide 512 by 8, we get a quotient of 64 with no remainder.

Therefore, 512 is a multiple of 8.

2 + 3 - 4 + (5 × 4)
=2 + 3 - 4 + 20
=5 - 4 + 20
=1 + 20
=21.