Correct Answer: harmony

Solution : The correct choice is the first option.

Explanation : In the given context, cacophony refers to a harsh, discordant mixture of sounds. The antonym harmony contrasts with this by representing a pleasing arrangement of sounds where everything works together in a synchronised and pleasant manner.
The meanings of the other options are as follows:

• Alimony refers to financial support paid by one spouse to another after a divorce.
• Bedlam signifies a state of uproar, confusion, or chaos.
• Euphony denotes a pleasant, harmonious sound or combination of sounds.

Therefore, the correct answer is harmony.