Hi Brittany!

This one's sneaky. The indicated carbon (in this case, CARBONS) are really hard to spot because no colours are used. In Reaction 2, there are two black dots on the product side. THESE ARE THE INDICATED CARBONS. Both have the same molecular geometry. We need to determine it.

An adduct is a prodUCT formed during the ADDition of two molecules. More specifically, it's the product formed when two molecules add together to form only ONE product, with nothing left over. Notice that the Diels-Alder reaction has two reactants and one product, and is therefore a perfect example of this.

Focusing on the indicated carbons, now:

They are each attached to FOUR "things", and are therefore sp3-hybridized and tetrahedral.