Fifty miles __ not a long distance.

Correct Answer: (B) is Subject-verb agreement with collective measurements is a classic and frequently tested grammar point in NTRCA English. The Core Rule — Collective Measurement as Subject: When a sum, distance, amount, or quantity of money is used as the subject of a sentence, it is treated as a SINGLE UNIT and takes a SINGULAR verb — even if the number appears plural. Application: "Fifty miles is not a long distance." — "Fifty miles" is treated as a single distance (one measurement unit), NOT as 50 separate miles. — Therefore, it takes the singular verb "is." More Examples of This Rule: — "Ten dollars is all I have." ✓ — "Three hours is a long time to wait." ✓ — "Two kilometres is not far from here." ✓ — "Sixty percent of the work is done." ✓ Contrast — When Plural Verb is Used: If the items are considered individually (not as a single unit): — "The fifty miles were covered in stages." (each mile counted separately) — But in most everyday contexts, measurements → singular verb. Why others are wrong: ✗ "are" — plural verb; wrong because "fifty miles" is a singular collective measurement ✗ "have been" — present perfect; wrong tense and number ✗ "were" — past tense; the sentence is a general truth, not a past event Source: English Grammar in Use — Raymond Murphy; NTRCA Question Bank.