1.There were dirty marks on her trousers _____ she had wiped

1.There were dirty marks on her trousers _____ she had wiped her hands.
A.where B.which C.when D.that
2.He studied hard and later became a well-known writer._____his father had expected.
A.that was what B.what was that C.which was what D.which was that
3.I work in a business____almost everyone is waiting for a great chance.
A.how B.which C.where D.that
4.The journey around the world took the old sailor nine months,_____the sailing time was 226 days.
A.of which B.on which C.from which D.fo which