The following sentence has been split into four segments. Identify the segment that contains a grammatical error.
Urgent activities are those things / that you must do immediately, / as they require quick action / and cannot be put on.

Correct option is A

Option (a) contains an error.
Error identification: The phrase "cannot be put on" is incorrect in this context. The correct phrase should be "cannot be put off."
Grammatical Rule used: The phrase "put off" means to postpone, which makes sense in the context of the sentence where urgent activities cannot be delayed.
Corrected sentence: "Urgent activities are those things that you must do immediately, as they require quick action and cannot be put off."
Detailed explanation of error: The phrasal verb "put off" is required to correctly convey the idea of delaying or postponing an action. "Put on" does not fit this context.