J, K, L, M, N and O are the members of a family. Professions of all members are different. If (i) the family has two married couples, (ii) 'M' is a doctor and his wife is an engineer, (iii) 'J' is the granddaughter of 'O' and sister of 'L', (iv) 'K' is the grandfather of 'L' and is married to a teacher, (v) 'L' is a clerk and his mother is 'N', then who is the wife of 'M'?