C. 0 or 1
This question was addressed to me during an interview for a job.
This intriguing question originated from Properties of Transfer Functions in chapter S-Domain Analysis of Network Theory
Best explanation: The degree of numerator polynomial and denominator polynomial in a driving point function may differ by zero or one. And the polynomials P(s) and Q(s) may not have any missing terms between the highest and lowest degrees unless all even or odd terms are missing.