Answer:
B. Janet's expertise is in low supply and high demand.
Explanation:
Sam's transcription occupation is in high supply and low demand ; this means that there are a lot more transcriptionist available to work than open positions employers are offering. This pushes down the salary and that explains why Sam earns $30,000 per year. Janet's occupation on the other hand pays high salary of $73,000 per year which indicate that jet propulsion specialists are in high demand but there is a shortage of expertise in the market.