Answer:
C 4,200
Explanation:
THE FIRST ANSWER I PUT WAS INCORRECT 70 TIMES 60 = 4,200 because 70 has one 0 and 60 has one 0 use that as a strategy so there's two 0,s when you combine it and its at the end of 4,200 so sice 6 times 7 or 7 times 6 = 42 put the two 0,s at the end and add it to 42 then you get 4,200 or 4200 you don't have to put the comma but it helps let you know 4,000 is part of the thousands and lets you know to seperate it from the hundreds so it's better to add the comma if you want to if you don't want to then it's okay but you might get a answer wrong without a comma so the answer is C 4,200!!!!!!!!!!