What would be the mass of the electron given the excess charges and the charge to mass ratio being 1.85x 10^7 c/g? PLEASE HELP cont. below!?

Imagine an alternate reality. The Thomson cathode ray experiments arrived at a charge to mass ratio, 1.85×107 C/g for the electron. If when Milikan performed the oil drop experiment he found that a series of droplets had excess charges of 4.29×10-19 C, 2.57×10-19 C and 3.43×10-19 C, what could be the mass of an... show more Imagine an alternate reality. The Thomson cathode ray experiments arrived at a charge to mass ratio, 1.85×107 C/g for the electron. If when Milikan performed the oil drop experiment he found that a series of droplets had excess charges of 4.29×10-19 C, 2.57×10-19 C and 3.43×10-19 C, what could be the mass of an electron?
2.57×10-19 grams
2.32×10-26 grams
1.86×10-26 grams
4.64×10-27 grams
3.43×10-19 grams
Update: please explain HOW to come to an answer!