12. Two kangaroos Bo and Ing start to jump at the same time, from the same point, in the same direction. After that, they each make one jump per second. Each of Bo's jumps is $6 \mathrm{~m}$ in length. Ing's first jump is $1 \mathrm{~m}$ in length, his second is $2 \mathrm{~m}$, his third is $3 \mathrm{~m}$, and so on. After how many jumps does Ing catch Bo?
A 10
B 11
C 12
D 13
E 14