The right option is B) gerund phrase
A gerund phrase is a noun formed with a verb ending in 'ing'. A gerund phrase always begins with a gerund, is always the subject, and often contains any modifiers with other objects. Words such as walking, laughing and dancing can all be used as gerunds. In sentence seven from the question given, scanning images and calculating sizes and positions are both examples of gerund phrase. (Scanning and calculating is the gerund. Scanning images and calculating sizes and positions is the gerund phrase which acts as a subject in the sentence).
The correct answer is gerund phrase. A gerund phrase is a group of words that functions as a noun and cannot stand alone. Gerunds are "ing" words that function as nouns. Participial phrases also involve "ing" words, but these do not function as nouns. In sentence seven, scanning images and calculating sizes and images form a compound subject, which by definition must be a noun or pronoun. So its be
