Sentence Correction: Parallelism and Grammar

Directions: This question presents a sentence, all or part of which is underlined. Beneath the sentence you will find five ways of phrasing the underlined part. The first of these repeats the original; the other four are different. If you think the original is best, choose the first answer; otherwise choose one of the others.

The increased popularity and availability of televisions has led to the decline of regional dialects, language variations which originate from diverse ethnic and cultural heritages and perpetuated by geographic isolation.