Correct Answer: Abundant

Solution : The fourth option is correct.

Scanty means lacking in quantity or insufficient, indicating a small or inadequate amount of something.
Abundant means present in large quantities, more than enough, or plentiful.
So, in the context of opposites, abundant is the antonym that conveys the idea of having more than enough or being plentiful, contrasting with the limited or insufficient nature of scanty.

The meanings of the other options are:

Expedient: Expedient can refer to anything that serves one's immediate interests or goals, even if it is not necessarily the most principled or morally upright choice.

Paltry: Paltry is an adjective that describes something as being small, meagre, trivial, or of little value.

Nasty: It often implies that it is unpleasant, filthy, or repulsive.

Therefore, the correct answer is abundant.