An element X has two natural isotopes $$5^{10}X$$ with atomic mass 10.013 u and $$5^{11}X$$ with atomic mass 11.009 u. Relative abundance of these isotopes in nature has been recorded 19.8% and 80.2% respectively. On the basis of these data, average atomic mass of element X is close to

A

10.210 u

B

10.511 u

C

10.799 u

D

10.812 u