Answer:
Option A
Step-by-step explanation:
A person attempting to make a phone call while waiting for a meeting, is starting one task before another begins. So, it's not option B since multitasking is completing two or more tasks as once. It's not option C because sequential tasking, is beginning one task and not starting another in till that initial task is completed. It's not cleaving tasks or option D because cleaving tasks just means clinging to one task. Your best answer is option A or "combining tasks", since you are completing a phone call while waiting for your meeting. It means you are completing one task while waiting for another one to start.
Hope this helps.