To find the unit rate for 1 bag of chips given that 5 bags cost $6.25, you can calculate the cost of 1 bag by dividing the total cost by the number of bags:
\[ \text{Cost of 1 bag} = \frac{\text{Total Cost}}{\text{Number of Bags}} = \frac{6.25}{5} \]
Calculating this gives:
\[ \frac{6.25}{5} = 1.25 \]
Therefore, the unit rate for 1 bag of chips is $1.25.
So the answer is A. $1.25.