Identify the infinitive phrase in the following sentence: the teacher's plan to go on a field trip was foiled by rain. a. the teacher's plan b. to go on a field trip c. was foiled d. by rain

The infinitive phrase in the following in the sentence is B) To go on a field trip. 

The details that best show evidence of tribal traditions are, "never in the history of his people had a man married a woman who spoke a different tongue” and "it has never been heard," was the verdict of an old man speaking a few weeks later.