Output of C code

Question

Why is the output of this code 40?
https://code.sololearn.com/cH7l8SWdCZRT/#c

Answer 1

A Union size is the biggest size among all data types in that in that union. So
int a[10]; requires highest bytes that is 4*10=40
4 size of int.
10 size of array length...

Answer 2

Thank you!