Answer:
A). A friend called me: clause
B). The building across the street: Not a clause
C). Looks pretty at night: Not a clause.
D). Because the boy shouted: clause
Step-by-step explanation:
A clause is defined as the grammatical construction that consists of a subject and a verb. In the given question, the first and the last sentence exemplify clause as they involve subjects 'A friend'(in the first) and 'the boy'(in the last) and the verbs 'called'(in the first) and 'shouted'(in the last). However, the first one is an independent clause as it offers a complete thought while the last one is a dependent clause as it requires a principal clause to accomplish its meaning. The second and third options are not clauses as the former miss a verb while the latter does not contain a subject.