A. & D. are the correct answers
To answer this, you square the first 2 numbers in the sequence, and then add them together. You then square the 3rd number and put it equal to the first numbers that you added together. If the two sides equal each other, it is correct!
Ex.:
10, 24, 26
10^2 + 24^2 = 26^2
100 + 576 = 676
676 = 676
18, 24, 30
18^2 + 24^2 = 30^2
324 + 576 = 900
900 = 900