The following sentence contains a blank that must be filled with the correct phrasal verb so that the meaning is clear and natural. Food was packed, and they __________, a merry, delighted party.

Introduction:
This question tests your understanding of common English phrasal verbs used to describe the beginning of a journey or movement. The sentence talks about food being packed and a group of people leaving together, so you must select the phrasal verb that correctly expresses "to begin a journey".

Given Data / Assumptions:
- The incomplete sentence is: "Food was packed, and they __________, a merry, delighted party."
- Options: "went off", "start off", "cut off", and "set off".
- The context suggests that after packing food, the group leaves for some outing or trip in a happy mood.

Concept / Approach:
In English, "set off" is a standard phrasal verb meaning "to begin a journey" or "to start travelling". While "start off" can also mean "begin", its form in the sentence must agree with the past narrative. "Went off" and "cut off" do not naturally express the idea of happily starting a trip. The correct approach is to match the verb to both the grammar of the sentence and the implied meaning of departure.

Step-by-Step Solution:
Step 1: Understand the context: Food is packed, which usually happens before a journey or picnic.Step 2: Try option D, "set off": "Food was packed, and they set off, a merry, delighted party." This sounds natural and clearly means they began their trip.Step 3: Test option A, "went off": "Food was packed, and they went off, a merry, delighted party." Although not impossible, "went off" can also mean exploding or suddenly leaving, and it is not the usual phrasal verb for starting a planned journey.Step 4: Test option B, "start off": "Food was packed, and they start off, a merry, delighted party." This is grammatically wrong because the sentence is in past tense and requires "started off".Step 5: Test option C, "cut off": This means interrupt or separate and does not match the context at all. Therefore, "set off" is the best and correct choice.

Verification / Alternative check:
Consider other typical examples: "They set off early in the morning for the hills," or "We set off after breakfast." These show that "set off" is widely used for beginning journeys. In contrast, "went off" can mean a bomb exploded, and "cut off" usually refers to loss of connection or separation. Therefore, in this cheerful picnic like context, "set off" is the natural collocation.

Why Other Options Are Wrong:
Option A, "went off", is not the ideal choice because it can carry unintended meanings and is less precise for a happy, planned departure. Option B, "start off", is in the wrong tense; the sentence needs past tense "started off" to match "was packed". Option C, "cut off", has an entirely different meaning related to interruption or isolation. Only option D, "set off", correctly and neatly expresses the idea of beginning a journey.

Common Pitfalls:
Students sometimes choose a phrasal verb based only on the word "off" without considering the exact meaning. Another common error is ignoring tense agreement; many candidates pick "start off" because it seems familiar, but they fail to notice that the surrounding verbs are in the past. To avoid such mistakes, always read the entire sentence, identify the time frame, and choose the phrasal verb that both fits the tense and expresses the intended action.

Final Answer:
The correct phrasal verb is set off, so the sentence reads, "Food was packed, and they set off, a merry, delighted party."