The sentence fragment present in those sentences is...
Regina and her younger sisters.
A preview is generally a first look at something before it is released (like when a film is previewed before it’s released to the general public).
The correct answer would be B. Adjective.
A participial phrase would appear to be a verb but it functions as an adjective in a sentence. It describes a noun. It consists of a present participle, past participle, or any modifiers and objects.
