Correct Answer: Mean

Solution : The fourth option is correct.

Explanation:
Congenial means pleasant to spend time with because their interests and character are similar to your own. Mean refers to a person who has to put people down to make themselves feel good about themselves.
The meanings of the other options are as follows:

• Mild means gentle or not harsh in nature, temper, or flavour.
• Mellow means soft, matured, or well-developed, often describing a smooth and pleasing character or flavour.
• Merciful means showing compassion and forgiveness, characterised by a willingness to alleviate or pardon suffering.

Therefore, the correct answer is mean .