If the coli form bacteria is present in a sample of water, then the coli-form test to be conducted is (i) Presumptive coli-form test (ii) Confirmed coli-form test (iii) Completed coli-form test$?

• A. Only (i)
• B. Both (i) and (ii)
• C. Both (i) and (iii)
• D. All (i), (ii) and (iii)