# What are the different types of catalysts used in catalytic hydrogenation of alkynes?

This is a question from Org. Chem. by Solomons, Fryhle & Snyder, adapted for JEE by M.S. Chouhan :

1. In the first step, I expected that the reaction would stop at alkene formation via syn addition of $\ce{H_2}$ since Lindlar catalyst is poisobed and heterogeneous. What are some other other poisoned catalysts that stop at alkene?

2. In the second step, I expected syn addition of $\ce{D_2}$ since $\ce{Pd-C}$ is a heterogeneous catalyst, forming product (a). But the answer given is (c) — does this mean that some heterogeneous catalyts can give anti addition, or is it just an error on the adapting author's part?