194c tds on payment to contractors and sub-contractors

Hi there.

Consider the situation:

I have four contractors A,B,C,D

The following Payments I have paid to them.

A- Rs.25000,15000,25000

B-Rs.25000,25000

C-Rs.10000,Rs.15000

D-Rs.25000

How do I take the payments for calculating TDS?

Should I take sum of all payments for seeing whether it has crossed Rs.100000 or Should I take Individual contract wise?

If it is Individual wise I don't have to deduct any TDS right? (As it has not crossed the limits of Rs.100000/Rs.30000)

Kindly clarify the situation.

Thanks and regards