6. (10 points) Grandma takes 3 minutes to fold one paper crane, and she needs to rest for 1 minute after each one. Grandma starts folding at 2:30. When she finishes the 5th paper crane, it is ( )
A. 2:45
B. 2:49
C. 2:50
D. 2:53
【Answer】Solution: $1 \times(5-1)=4$ (minutes) $3 \times 5=15$ (minutes)
2:30 + 4 minutes + 15 minutes $=2$ :49 Answer: When she finishes folding the 5th paper crane, it is already 2:49; therefore, the correct choice is: B.