'Waiter' is related to 'Restaurant' in the same way as 'Worker' is related to '_________'.

A) Factory (Correct) – A Worker typically works in a Factory, just as a Waiter works in a Restaurant.

B) Shop (Incorrect) – Shop workers are usually called Salespersons or Clerks.

C) House (Incorrect) – House workers are typically Maids or Domestic Helpers.

D) School (Incorrect) – School workers are usually Teachers or Staff.

Thus, the correct option is (A) Factory.