The advantages of upgrading computer hardware include improved performance, enhanced speed, increased storage capacity, and better overall system efficiency.
In the statement provided, the correct completion would be:
upgrading the A. RAM usually speeds up the computer, while adding a(n) B. hard drive will increase the system's storage capacity.
This means that increasing the RAM typically enhances multitasking capabilities and overall responsiveness, while adding a hard drive helps to store more data and applications.