Determine if f(x) is differentiable at x = a using the definition of differentiability. Determine if the function f left parenthesis x right parenthesis equals cube root of x is differentiable at x equals short dash 8. If not, identify why. A.) f left parenthesis x right parenthesis equals cube root of x is not differentiable at x equals short dash 8 because f apostrophe left parenthesis short dash 8 right parenthesis is not defined. B.) f left parenthesis x right parenthesis equals cube root of x is differentiable at x equals short dash 8. C.) f left parenthesis x right parenthesis equals cube root of x is not differentiable at x equals short dash 8 because limit as x rightwards arrow short dash 8 of cube root of x does not exist. D.) f left parenthesis x right parenthesis equals cube root of x is not differentiable at x equals short dash 8 because f left parenthesis short dash 8 right parenthesis is not defined