Suppose Xijk is a decision variable that means assign nurse i to shift j on day k. There are 10 nurses, 3 shifts (1=day, 2=evening, 3=night), and 7 days (1=Monday through 7=Sunday). Question: What is the constraint that mathematically represents the rule that nurse 4 can be assigned to at most one shift on a Friday (choose ONLY ONE ANSWER)? Group of answer choices X415 + X425 + X435 = 1 X145 + X245 + X345 = 1 X415 + X425 + X435 < = 1 X145 + X245 + X345 < = 1