Fill in the blanks with the suitable modals in the following sentences :

should; would; must; mustn’t. 

(a) This is a first class compartment and you have a second class ticket. So you ………. sit here. 

(b) …………………. you mind giving me a lift upto Civil Lines? 

(c) We ………………….. obey our elders. 

(d) Half yearly examination are near. So you …………………. revise your course.