$$7\times {{10}^{9}}\times 5\times {{10}^{2}}=3.5\times {{10}^{12}}$$ 
A computer can do $$7\times {{10}^{9}}$$ operations per second. Then, it can do~\uline{~~~~~~~~~~}~operations in $$5\times {{10}^{2}}$$ seconds. 
Options:
A: $$35\times {{10}^{10}}$$ 
B: $$3.5\times {{10}^{11}}$$ 
C: $$3.5\times {{10}^{12}}$$ 
D: $$3.5\times {{10}^{19}}$$ 
E: $$3.5\times {{10}^{18}}$$ 