Answer
$H_a; µ \lt 3$ matches with (d),
the null hypothesis being $H_0; µ\geq3$ (see attached graph).
Work Step by Step
The alternative hypothesis $Ha:μ \lt3$ means that μ takes on all values less than 3, and that is represented by graph (d).
The null hypothesis is the opposite: $Ho:μ\geq3$. See the attached graph above.