Answer:
420 unique combinations.
Step-by-step explanation:
Fundamental counting principle:
States that if there are p ways to do a thing, and q ways to do another thing, and these two things are independent, there are p*q ways to do both things.
One object from each set:
2 from one set, 5, 6 and 7 by others. Sets are independent, so, by the fundamental counting principle:
2*5*6*7 = 10*42 = 420
420 unique combinations.
