2. The sequence $\{2 n+1\}$ is cyclically divided into groups of one, two, three, and four terms as follows: $(3), (5,7),(9,11,13),(15,17,$ $19,21),(23),(25,27),(29,31,33),(35,37,39,41),(43), \cdots$. What is the sum of the numbers in the 100th parenthesis?
A. 1992
B. 1990
C. 1873
D. 1891
2. Since $100=4 \times 25$, the 100th parenthesis contains 4 numbers, which are the 247th to 250th terms of the sequence $\{2 n+1\}$. Their sum is equal to $(2 \times 247+1+2 \times 250+1) \times 2=1992$.