The product of 0.1400 × 6.02 × 1023 will have how many significant figures?

3 significant figures.

0.1400 has 4 sig figs, 6.02 has 3, and 1023 has 4. when calculating significant figures for a multiplication or division equation, the product or quotient will have the same amount of significant figures as the number with the least amount of significant figures (in this case: 6.02).