Explanation:

To determine the largest unit of storage among the given options, we need to understand the standard hierarchy of digital storage units. The hierarchy, from smallest to largest, is typically: Bit < Byte < Kilobyte (KB) < Megabyte (MB) < Gigabyte (GB) < Terabyte (TB) < Petabyte (PB), and so on. Let's compare the options provided: (a) GB (Gigabyte), (b) KB (Kilobyte), (c) MB (Megabyte), (d) TB (Terabyte). Arranging these in ascending order of size, we have: $\text{KB} < \text{MB} < \text{GB} < \text{TB}$. Therefore, Terabyte (TB) is the largest unit among the choices. Option (a) GB, (b) KB, and (c) MB are all smaller than TB. Option (e) 'None of these' is incorrect because TB is clearly the largest among the listed units.