What does the case of the old French polisher illustrate?

A、Moreandmorepeoplehaveacceptedthatalthoughtheyareoldtheyhavetolearnnewskills.
B、Redundantworkershavetolearnnewskillseventhoughtheyareold.
C、Sometimespeoplearetoooldtolearnsomethingnew.
D、Peoplearenevertoooldtolearnsomethingnew.