$$4\times {{10}^{9}}\times 5\times {{10}^{2}}$$  $$=20\times {{10}^{9}}+2$$  $$=2\times {{10}^{1}}\times {{10}^{11}}$$  $$=2\times {{10}^{1+11}}$$  $$=2\times {{10}^{12}}$$ 
One kind of computer can make $$4\times {{10}^{9}}$$ operations per second.~ How many operations can it make in $$5\times {{10}^{2}}$$ seconds? 

A. $$4\times {{10}^{11}}$$ 
B. $$2\times {{10}^{11}}$$ 
C. $$2\times {{10}^{12}}$$ 
D. $$20\times {{10}^{18}}$$ 
E. $$2\times {{10}^{19}}$$ 