Sarah comes from a lower-middle-class family. her parents were teachers and relied on both their incomes to run their household. sarah got into medical school on a scholarship and is now a doctor in a well-reputed hospital. sarah's movement to the upper-middle class is an example of

Intergenerational mobility

Explanation:

When a change of socio-economic status takes place in between generations it is known as Intergenerational mobility.

Here, Sarah is from a lower-middle-class family i.e., her parents belongs to the lower-middle-class. Sarah became a doctor with the help of a scholarship. She was earning more than what her parents were earning. So, she moved up to the upper-middle class. This happened between her and her parents generation.

Hence, Sarah's movement is best described as Intergenerational mobility.