Fill in the blank (vii).

Here, size is the correct option as size is the relative extent of something, here it is the tiger. Volume is the amount of space that a substance or object occupies, or that is enclosed within a container. Amount is a quantity of something and dimension is a measurable extent of a particular kind, such as length, breadth, depth, or height. Here, the passage is talking about the size of tiger, and not about its volume, amount or dimensions. Other options are irrelevant in this context.