The answer is <em>C: twisting the handlebars quickly and wiggling the front wheel</em>.
1. Twisting the handlebars quickly: "There is a third movement of the handle bars --a quick twist in the direction the machine is leaning if about to fall."
2. Wiggling the front wheel: [prevent the fall by throwing the balance the other way] " a similar result is accomplished by wiggling the front wheel...a continuous wiggle --changing the balance...-- is necessary to keep it upright."
Yes this sentence it correct, except there should not be a space between table and the period. :)
