Q$1.$ Chlorine $($average atomic mass $=35\mathrm{.}453a)$ exists in two isotopes in nature, Cl$-35(34\mathrm{.}9689$ amu, abundance $76\%).$ What is the atomic mass of the second isotope Cl$-37?$

a$)35\mathrm{.}990a$

b$)34\mathrm{.}9867a$

c$)36\mathrm{.}9858a$

d$)35\mathrm{.}9371a$

e$)36\mathrm{.}0087a$