Which dimensions can create more than one triangle? a. three angles measuring 75°,45°, and 60°. b. 3 sides measuring 7, 10, 12? c. three angles measuring 40,50,and60°? d. 3 sides measuring 3,4,and 5

This is vague.  Any dimensions that make a triangle can make more than one, just draw another right next to it.  What's really being asked is which dimensions can make more than one non-congruent triangle.

A. Three angles measuring 75°,45°, and 60°.

That's three angles, and 75+45+60 = 180, so it's a legit triangle. The angles don't determine the sides, so we have whole family of similar triangles with these dimensions.  TRUE

B. 3 sides measuring 7, 10, 12?

Three sides determine the triangles size and shape uniquely; FALSE

C. Three angles measuring 40°, 50°, and 60°?

40+50+60=150, no such triangle exists.  FALSE

D. 3 sides measuring 3,4,and 5

Again, three sides uniquely determine a triangle's size and shape;  FALSE