A bag contains 8 balls, of which 5 are green and 3 are red. The probability that two balls chosen at random are of the same colour is:

• Correct answer
  A

  $\frac{13}{28}$.
• B

  $\frac{12}{28}$.
• C

  $\frac{15}{28}$.
• D

  $\frac{14}{28}$.

Hence, the correct answer is option: 'A'.