Select the word or phrase in the sentence that is not used correctly : The man's heart attack scared him badly, and he decided having a regular check-up from then on.
Correct Answer: A
Rationale: The word "having" in the original sentence is grammatically incorrect. After the verb "decided," the correct structure requires the infinitive form of the verb, which is "to have." Therefore, the phrase should read "decided to have a regular check-up." This structure clearly indicates the man's choice to start a new action. Additionally, the phrase "from then on" effectively emphasizes the beginning of this new habit of regular check-ups, reinforcing the need for the infinitive form. Thus, option A is the most appropriate and grammatically correct choice.
Nokea