What is the sum of the squares of the first 20 natural numbers (1 to 20)? Choose the most appropriate option:
A) 2870  B) 2000  C) 5650  D) 6650  E) 7650

Rationale: n ( n + 1 ) ( 2 n + 1 ) / 6 20 ( 21 ) ( 21 ) / 6 = 2870 answer : a
Answer: A