To determine how much May should write the check for, we need to subtract the cash payment from the total cost of the fridge.
Total cost of the fridge: $1368.25
Cash payment: $497.80
Now, we subtract the cash payment from the total cost:
\[ \text{Balance} = \text{Total cost} - \text{Cash payment} \] \[ \text{Balance} = 1368.25 - 497.80 = 870.45 \]
May should write the check for $870.45.
So, the correct answer is c. 870.45.