let n>=t>=1 be postiive integer

Give a bijection of f: A -> B where

• A is the set of multisets of size n with t types where every type has an odd number of elements where n-t is even and
• B is the set of multisets of size (n-t)/2 with t types.

and determine the size of A.

In both of your solutions, you need to clearly define your bijection f: A -> B