The answer is d and e (together), a respectively. Please explain why

Consider the following business process: a b d Which execution logs would be possible for a single run of this process? a) a-b-c-d-e- b) b-c-d-a-e c) a-e d) a-e-b-c-d-e e) c-b-d-e-a-e Suppose the leftmost gateway is not of type AND, but of type Event- based XOR. Further suppose that a, b, and care activities that receive a message at time t+1, t+3, and t+2 respectively. Which execution logs would be possible for a single run of the process with starting time t?: a) a-e b) b-d-e c) C-d-e d) a-c-b-d-e e) a-c-b-d-e-e