The probability that a student knows the correct answer to a multiple choice question is $\dfrac{2}{3}$ . If the student does not know the answer, then the student guesses the answer. The probability of the guessed answer being correct is $\dfrac{1}{4}$. Given that the student has answered the question correctly, the conditional probability that the student knows the correct answer is
- $\dfrac{2}{3} \\$
- $\dfrac{3}{4} \\$
- $\dfrac{5}{6} \\$
- $\dfrac{8}{9}$