help plz!!!

dear friends...

i have a doubt u/s 40a(3) for cash payments made exceeding 20000 in a day...

my question is..... if i have five different purchase bills for different dates of Rs.1 lac each from a single person.....n i want to make payment on one single day.....so what should be my maximum payment so as not to be charged under section 40a(3):

a. Rs.20000 per bill, i.e. 20000*5=100000

or

b. only Rs.20000 irrespective of number of bills.