The correct answer is: D. Terabyte (TB)
A gigabyte (GB) is a unit of information or computer storage equal to one billion (1,073,741,824) bytes. A kilobyte (KB) is a unit of information or computer storage equal to one thousand (1,024) bytes. A megabyte (MB) is a unit of information or computer storage equal to one million (1,048,576) bytes. A terabyte (TB) is a unit of information or computer storage equal to one trillion (1,099,511,627,776) bytes.
Therefore, a terabyte is the largest unit of storage listed in the options.