What device enables a pc to retrieve a specific row of data from system memory and place it on the external data bus?

Memory controller chip is right. 

Memory Controller Chip.It is a digital circuit that manages the flow of data going to and from the computer's main memory.

The correct answer is no.

Ibelieve the answer is: b.  use a different transition for every slide to keep the audience's attentiona. that would make it boringc. sound effects might be distracting and some people might find it annoyingi hope that : )