All questions of Modal Verbs for Class 8 Exam
"Could" is a polite way to ask for permission or inquire about a possibility.
"Should" is used to suggest an appropriate action or give advice in this context.
"Should" is used to express an expectation or likelihood that there is or was a famous shop at this location.
"Will" is used to express a firm intention or determination to investigate the matter.
"Must" is used to indicate a necessity or requirement. It implies that settling of the audience is necessary before the doors are closed.
Could is the correct answer.
Why? Well, first you need to consider the context. Obviously, by common sense, it is something bad that has occured to the speaker and he/she is questioning the possibility of the incident and saying that morally
"Need not" means it's not necessary or obligatory to visit them; making a phone call is sufficient.
"Could" is used to express past ability or past events. In this context, it refers to Juan's ability to speak well when he was two years old.
"Supposed to" implies an obligation or expectation to wait in the lobby until a certain condition (receptionist calling again) is met.
"Could" is used to express past ability or possibility, indicating the potential for winning the tournament in the past.