Correct Answer: Subsistance

Solution : The fourth option is the correct answer.

The incorrectly spelled word is "subsistance". The correct spelling is subsistence, referring to the state of remaining alive or continuing to exist, often with the basic necessities for survival.

The meanings of the other options are as follows:

• A benchmark is a standard or point of reference.
• A knight is a person granted the honorary title of knighthood.
• Aggravate means to make a situation or condition worse.