AMC 10B 2002 Problem 19

Suppose that \left\{a_{n}\right\} is an arithmetic sequence with

a_{1}+a_{2}+\cdots+a_{100}=100 \text { and } a_{101}+a_{102}+\cdots+a_{200}=200

What is the value of a_{2}-a_{1} ?

Answer Choices
A. 0.0001
B. 0.001
C. 0.01
D. 0.1
E. 1