The fragment that is made up of a complete predicate is option A. "could not be heard above the voices in the hallway"
In grammar, the predicate is defined as the part of the sentence that contains the verb and gives information about the subject.
Option A is the only option that contains a verb, in this case "could" and it is providing information about a subject we don´t know. The only options lack verbs,
They probably think like there frustarated or something (the character not them) the the reader probably would be weirded out or questionable or also frustrated
"the difficulty that both Chinese and Japanese immigrants face when they try to pass the immigration stations during that period is : Chinese and Japanese immigrants were restricted by law from entering united states"
"This was known as the exclusion act. The main purpose of this policy was to protect the job opportunities from the united states citizen that being threaten by the availability of cheap immigrant workers"
What are talking about? ( not being rude)
