Sample: Sally left school ... the ago of 16 and went to work ..a bank a)through/in b) out of/in c)under/around d)at/in

 Sample: Sally left school ... the age of 16 and went to work ..a bank a)through/in b) out of/in c)under/around d)at/in

С указанием конкретного возраста (age of 16) используется предлог at. С учетом этого, правильный ответ будет D: Sally left school at the age of 16 and went to work in a bank.