Run fast . . . . . . . . get your ticket.

Answer: Option D

Defining Coordinating Conjunctions:
Coordinating conjunctions are words like "and," "but," "or," "nor," "for," "so," and "yet." They connect words, phrases, or clauses of equal grammatical rank.

Option Analysis:
Option A: but - "But" indicates contrast. The sentence implies a cause-and-effect relationship, not a contrast. "Run fast, but get your ticket" suggests running fast *despite* getting a ticket, which is illogical.
Option B: as - "As" can indicate a cause-and-effect relationship, but usually implies simultaneity. "Run fast as get your ticket" doesn't make grammatical sense. It would need to be something like, "Run fast as you get your ticket".
Option C: otherwise - "Otherwise" introduces an alternative consequence. The sentence needs a consequence of *not* running fast, not an alternative. "Run fast, otherwise you won't get your ticket" is grammatically correct, but does not fit the implied meaning of the prompt.
Option D: and - "And" indicates addition or a continuation. The sentence structure implies a cause-and-effect relationship: running fast will lead to getting a ticket. "Run fast and get your ticket" perfectly expresses that relationship - running fast is the action to take to get the ticket.

Correct Answer: Option D (and)
The conjunction "and" appropriately links the two clauses, showing that running fast is the action required to achieve the desired outcome (getting the ticket). The sentence is grammatically correct and logically sound with "and".