Final answer:
To find the morning temperature after a drop of 31°F from 22°F, use the expression 22 + (-31).
Step-by-step explanation:
The student asked which expression can be used to find the temperature in the morning after a night when the temperature outside was 22°F and then dropped 31°F overnight. The correct expression is C. 22 + (-31), which is the initial temperature plus the change in temperature (noting that the temperature dropped, so the change is negative).