Right Answer is: C
Order – Order of an ordinary differential equation is defined to be the order of the highest order derivative occurring in the equation.
Hence its order is 2.
Degree – The degree of an ordinary D.E. is defined to be the exponent of the highest order derivative occurring in the equation provided the equation is made free from radical signs and fractional powers as far as the derivatives concerned
Since the given D.E. can not be written as a polynomial in all the Differential coefficients, the degree of the equation is not defined.