Answer:
A career ladder is a system where people can advance to higher levels of responsibility and compensation.
Step-by-step explanation:
Effective commentary is simply giving an opinion or an interpretation, analysis, or evaluation about details of an essay. It is simply making a point of what you read.
The sentence that is an example of effective commentary on the evidence used in the paragraph is option A because they gave their opinion on what a career ladder is; which is a system where people can advance to higher levels of responsibility and compensation.