Determine which kind of causal relationship is being described. Please circle or highlight the correct answer a. Exposure to Measles virus and measles i. Necessary and sufficient ii. Necessary but not sufficient iii. Sufficient but not necessary iv. Neither sufficient nor necessary b. UV exposure and melanoma i. Necessary and sufficient ii. Necessary but not sufficient iii. Sufficient but not necessary iv. Neither sufficient nor necessary c. Sexual abstinence and pregnancy prevention i. Necessary and sufficient ii. Necessary but not sufficient iii. Sufficient but not necessary iv. Neither sufficient nor necessary