To find out how long Jeff practiced during the week, we can multiply the number of practices by the duration of each practice.
Jeff has practice 3 times, and each practice is 1 hour long.
So, the total practice time is:
\(3 \text{ practices} \times 1 \text{ hour/practice} = 3 \text{ hours}\)
Therefore, Jeff practiced for 3 hours during the week.
The answer is A. 3 hours.