How to subtract one list from another, treating each elements as distinct, assuming the smaller list is a subset of the larger list?

Suppose that I have two lists of different sizes, the smaller of which is a subset of the larger, e.g.

a = {"A", "A", "A", "B", "B", "C"}
b = {"A", "B"}

How can I subtract b from a, treating each element as distinct, such that the result is {"A", "A", "B", "C"}?

One solution I can think of is to use

Merge[{Counts[a], -Counts[b]}, Total]

then reconstruct the result somehow, but is there a simpler way?

Answer

Fold[DeleteCases[##, 1, 1] &, a, b]

{"A", "A", "B", "C"}