Jay Ahmad, an auditor, has decided to use systematic selection of payments when testing the control that payments are supported by a suppliers invoice, a purchase requisition and a goods received note. Each payment comprises a sampling unit. There are 4000 payments made (numbered 14000) and the total amount of payments is $1 million. The sample size is 20 and the random start is 107. Given this information, the sample interval is:

Select one:

a. 200

b. 307

c. 4 000

d. Some other amount