Will odd numbers when added always make even numbers

The probability of contamination in batch 1 of a drug (event a) is 0.16, and the probability of contamination in batch 2 of the drug (event b) is 0.09. the probability of contamination in batch 2, given that there was a contamination in batch 1, is 0.12. given this information, which statement is true? a. events a and b are independent because p(b|a) = p(a). b. events a and b are independent because p(a|b) ≠ p(a). c. events a and b are not independent because p(b|a) ≠ p(b). d. events a and b are not independent because p(a|b) = p(a).