The first 28 terms contain these groups:

1. First group: 1 term ($1$)
2. Second group: 2 terms ($1, 2$)
3. Third group: 3 terms ($3, 2, 1$)
4. Fourth group: 4 terms ($4, 3, 2, 1$)
5. Fifth group: 5 terms ($5, 4, 3, 2, 1$)
6. sixth group: 6 terms ($6, 5, 4, 3, 2, 1$)
7. seventh group: 7 terms ($7, 6, 5, 4, 3, 2, 1$)

Counting up to the 28th term, we find the sum of these terms is 84.

Answer: (B) 84