To find the angle between the minute and hour hand at 8:30, we follow these steps:
- At 8:00, the hour hand is at the 8th position. The minute hand is at the 12th position.
- The angle between each hour on the clock is \( \frac{360^\circ}{12} = 30^\circ \).
- So, at 8:00, the hour hand is at \( 8 \times 30^\circ = 240^\circ \) from the 12 o'clock position.
- At 8:30, the minute hand is at the 6th position (30 minutes), which is \( 180^\circ \) from the 12 o'clock position.
- The angle between the hour and minute hands is the difference between their positions:
\( 240^\circ - 180^\circ = 60^\circ \).
Therefore, the angle between the two hands is \( 180^\circ - 60^\circ = 105^\circ \).
Thus, the correct answer is (B) 105°.