Answer:
gig economy
Step-by-step explanation:
Sarah is not working full time as in a permanent job. She is doing short term contract jobs which are temporary jobs often known as freelance jobs. Underemployed here means Sarah is not being underpaid or not having enough paid jobs and not making full use of all her skills. For example she has worked as an uber driver and a farmer which isn't what she studied and therefore not really making full use of her skills and being underpaid for someone who has a Master's degree