What problem is described in the excerpt?
At any rate, the new velocipede was propelled by pedals and cranks attached directly to the axel of the front wheel, which was slightly larger than the wheel behind it. Forward progress could be stopped or slowed by pedaling backward. However, with iron tires and only an ineffective steel spring under the seat to absorb bumps in the road, this velocipede was a challenge to ride. It quickly earned the nickname "boneshaker." In 1865, Lallement brought his boneshaker to Connecticut, where he filed a description of it with the federal government and received a patent.

A :the awkward look of the enlarged front tire

B: the challenges of stopping the velocipede

C: the discomfort of riding the velocipede

D: the obstacles to filing for a US patent