How to create list of tuple by distributing the key to every value element inside a Python dictionary?

Question

I have a python dictionary as follows:

A = {7: [21, 29, 43], 16: [20, 21, 37, 49], 21: [7, 16, 43], 29: [2, 7], 43: [7, 21], 46: [23, 36]}

I