The quality of products . . . . . . . . over time.

A. are degrading

B. have been degrading

C. have degrading

D. were degraded

Answer: Option B

Solution(By Examveda Team)

We would use 'have been' when the sentence subject is I, you, we, or the third person plural (the children have been studying grammar all morning; they have been studying all morning). If the sentence subject is a third-person singular noun (he, she, it, Courtney), we would use the phrase 'has been'.