Which shows another way to write 64?

a.
6 x 6 x 6 x 6

b.
6 x 4

c.
4 x 4 x 4 x 4 x 4 x 4

d.
6 + 6 + 6 + 6

i want to say a but i feel i maybe wrong.

M? aoc=96 ? space, m, angle, a, o, c, equals, 96, degree \qquad m \angle boc = 8x - 67^\circm? boc=8x? 67 ? space, m, angle, b, o, c, equals, 8, x, minus, 67, degree \qquad m \angle aob = 9x - 75^\circm? aob=9x? 75 ? space, m, angle, a, o, b, equals, 9, x, minus, 75, degree find m\angle bocm? bocm, angle, b, o, c: