To represent the inequality \( y < 3 \) graphically:
- You would use an open circle on the number 3, indicating that 3 is not included in the solution (because the inequality is strictly less than, not less than or equal to).
- You would shade everything below the line \( y = 3 \) (to represent all values less than 3).
Therefore, the correct answer is: an open circle on 3 shading everything to the left of 3.