A bag contains $10$ white balls and $5$ blue balls. A ball is drawn from the bag and its color is noted. This ball is put back in the bag along with $3$ more balls of the same color. A ball is drawn again from the bag at random. The probability that the first ball drawn is blue, given that the second ball drawn is blue, is:
- $1/3$
- $3/4$
- $8/9$
- $4/9$
