Which is the best way to write the underlined portion of this sentence?

— ExhibitC

Sentence 9:Emergency teams have reported valuable information about CO levels, for example, one metropolitan area experienced a problem with CO levels that caused hundreds of alarms to go off during the first season they were available.

Which is the best way to write the underlined portion of this sentence? If the original is the best way, choose optionA.

A. levels, for example, one

B. levels.For example, one

C. levels, as an example, one

D. levels, for example there was one

E. levels, one

Answer: B