If the conjugate of a complex number is $\large\frac{1}{i-1},$ then the complex number is?

Question

(A) $\large\frac{1}{i-1}$ (B) $\large\frac{-1}{i-1}$ (C) $\large\frac{1}{i+1}$ (D) $\large\frac{-1}{i+1}$