It really is hard to say because there are many slots and we do not know what your teacher is teaching. I have seen a lot of teachers teaching out of date material. With that said, here is a list from best to worst.
PCI Express x16
PCI Express x1
AGP
PCI
This is list is based on greatest to least and base on the bandwidth read and write speed.
The correct answer is letter c. exhaust manifolds. Most V-type engines use two exhaust manifolds, one attached to each cylinder head. An exhaust manifold in automative engineering refers to the collection of the exhaust gases from different cylinders into another single pipe.
Client server network as it has a powerful server which provides all the networks required on the network. Files are usually backed up regularly.