Which sentence contains the underlined word that pertains to transitioning between different social classes?

Question

A. Jack's father operates the mobile library to reach communities without access to the local library.
B. After 3 days of rest, Alexa was back on her feet and mobile once more.
C. Bryce's family relocated from Dayton to Mobile, Alabama.
D. Ian's generation has been labeled as economically mobile, as people's financial states can change during their lifetimes

Answer 1

The sentence that contains the underlined word pertaining to transitioning between different social classes is:

D. Ian's generation has been labeled as economically mobile, as people's financial states can change during their lifetimes.