To determine which number is a solution of the inequality \( b > 2.1 \), we need to check each of the given numbers to see if it is greater than 2.1.
- –12: This is not greater than 2.1.
- 5: This is greater than 2.1.
- 1: This is not greater than 2.1.
- –8: This is not greater than 2.1.
Thus, the only number that is a solution of the inequality \( b > 2.1 \) is 5.