To how many significant figures should each answer be rounded?

equation A: (6.626× 10−34 J⋅s)(2.9979× 108 m/s)4.230×10−7 m=4.696001276596×10−19 J(unrounded)

After rounding, the answer to equation A should have
3 significant figures.
1 significant figure.
5 significant figures.
2 significant figures.
4 significant figures.

equation B: (6.022× 1023 atoms/mol)(0.667 g)20.18 g/mol=1.990×1022 atoms(unrounded)

After rounding, the answer to equation B should have
5 significant figures.
1 significant figure.
4 significant figures.
3 significant figures.
2 significant figures.