Concept: The question tests on the basics of Counting
Solution:
We have 7 boys of team 1 and 5 girls of team 2. The number of matches that can be played is 7C1 * 5C1 = 7 * 5 = 35
Similarly, We have 5 boys of team 2 and 3 girls of team 1. The number of matches that can be played is 5C1 * 3C1 = 15
The total number of matches is 35 + 15 = 50
Option C