Regarding business under 44ad of income tax

sir if a person doing business and filed itr under 44AD of income tax act.and he is not maintained books of account. he paid Rs. 150000 to contractor for doing job work. i want to ask can he paid Rs. 1,50,000 to contractor in cash. or it is necceesary to pay by cheque. also is there any liability to deduct TDS before payment to contractor.