Answer:
B)highest power of highest derivative
Explanation:
The degree of an equation can be determine by highest power of highest derivative.
Lets take following equation
[tex]3\left (\dfrac{d^4y}{dx^4} \right )^5+\left (\dfrac{d^3y}{dx^3} \right )^2+8\left (\dfrac{dy}{dx}\right )-6y=0[/tex]
Above equation is a differential equation.So the degree of equation is 5 and the order of the equation is 4.
So our option B(highest power of highest derivative) is right.