That's the conic section equation you get when
eliminating the parameter t. However there is
no way to answer your question, because we have
no information given about the values of a and b.
If a=-b, a≠0, the answer is A)
If a=0 and b≠0 or a≠0 and b=0, the answer is C)
If a and b have the same sign, the answer is D)
If a and b have opposite signs, the answer is B)
Edwin