Indium (In) is made up of 95.7% 115In and 4.3% 113In. The atomic mass of 113In is 112.904 amu . The atomic mass of 115In is 114.904 amu . What is the average atomic mass of a sample of indium?
a. 113.909 amu
b. 114.5 amu
c. 114.818 amu
d. +666+115.00 amu