The question is asking for the sample with more moles. In part a, you would convert both the 75g indium and 80g tellurium into their respective moles by dividing the substance molar mass.
0.65 > 0.63, so the 75g of indium contains more moles of atoms than the 80g of tellurium. Then do the same for part b. But for part c, you will have to divide by Avogadro's number (
) to convert atoms into moles. But since there are the same number of rubidium and iron atoms, there are the same amount of rubidium and iron moles.