${\left(201\right)}^2-{\left(200\right)}^2=$    

We know that difference of squares of any two consecutive natural numbers is their sum. So,200 and 201 are consecutive natural numbers.

Answer is $200+201=401$

Option(A): $\left(201+200\right)\left(201-200\right)=401\times 1=401$

Option(B): $200+201=401$

Option(C): 401

Option(D): $\left(200-201\right)\left(-200-201\right)=\left(-1\right)\times \left(-401\right)=401$