Question

A, b, b, c, c, c, d, d, d, d, . . . . . . find the 288th letter of this series.

Answer 1

I think it's y
hope it's right

Answer 2

A, b, b, c, c, c, d, d, d, d, . . . . . . find the 288th letter of this series.

anser is x.