Answer:
I like A the best; B also works.
Explanation:
Choices C and D do not result in centimeters, so are useless for this problem.
Though you can use the conversion factor 1 ft = 30.48 cm, I find it convenient to remember the conversion 1 in = 2.54 cm. The first factor with choice B gets you there:
... 1 yd = 3 ft = 3×30.48 cm = 91.44 cm . . . . . . can do in your head
As does choice A:
... 1 yd = 36 in = 36×2.54 cm = 91.44 cm . . . . . probably requires a calculator
The path you understand and that works for you is the "best" path.