What is the meaning of the intended word “harness” in the following sentence.

I unstrapped the harness from the dogs and let them rest after running for 12 hours straight.
a.
collars for identification
c.
leashes for walking
b.
straps attached to the dogs that allow them to pull the sled.
d.
none of the above


Please select the best answer from the choices provided

A
B
C
D