How do I use array notation for filter equal?

I want to simplify these 5 formulas into 1 formula.

=filter(A:.A,C:.C=B1)

=filter(A:.A,C:.C=B2)

=filter(A:.A,C:.C=B3)

=filter(A:.A,C:.C=B4)

=filter(A:.A,C:.C=B5)

The output/behaviour should be the identical to as if I was using these 5 formulas. Assume the data is completely inconsistent, e.g. has blanks, numbers, letters, and isn't ordered. Basically, it should work regardless of the data set and format.