Repetition structures, or loops, are used when a program needs to repeatedly process one or more instructions until some condition is met, at which time the loop ends. Many programming tasks are repetitive, having little variation from one item to the next. Vectorized mathematical code appears more like the mathematical expressions found in textbooks, making the code easier to understand. That is the difference. Hope I could help you on Brainly.com!
I would suggest the answer would be both A and D, mail merge is used to specify different field for different recipients.
