3. A frog starts climbing from the bottom of a 12-meter deep well at 8 o'clock. It climbs up 3 meters and then slides down 1 meter due to the slippery well wall. The time it takes to slide down 1 meter is one-third of the time it takes to climb up 3 meters. At 8:17, the frog reaches 3 meters below the well's mouth for the second time. How long does it take for the frog to climb from the bottom of the well to the mouth? ( ) minutes.
A. 22
B. 20
C. 17
D. 16
Analysis: Periodic problem.
The time to slide down 1 meter is three times the time to climb up 3 meters; the time to climb 1 meter and slide 1 meter is the same. Taking 3 meters of climbing and 1 meter of sliding as one cycle, when the frog is 3 meters away from the well's mouth, it has climbed 4 cycles plus 1 meter, taking 17 minutes. Therefore, the time the frog takes to climb $1 \mathrm{~m}$ or slide $1 \mathrm{~m}$ is 1 minute. $(12-3) \div(3-1)=4 \cdots 1$, the frog takes 5 cycles to climb from the bottom of the well to the mouth, then climbs another $2 \mathrm{~m}$, taking $5 \times(3+1)$ $+2=22$ minutes, choose $\mathrm{A}$.