A. Work steadily and methodically. Have a method of attack on each type of problem. Avoid galloping off bareback. C. One, and only one, of these options is correct in terms of the question. All problems have been thoroughly tested.
Every word is there on purpose, and every needed word has been included.
Ambiguities are deliberate, and a solution has been supplied. Avoid oversubtlety - don't make the test harder than it is. Keep track of time, but don't be possessed by it. Resist pressure by working at the fastest pace that is productive for you. Many people don't finish.