Based on the passage about the Alaska pipeline, choose the option that correctly states the daily capacity of the pipeline.

Introduction / Context:
This comprehension question focuses on a numerical detail in the passage about the Alaska pipeline. The text states the pipeline diameter and then gives its maximum daily capacity in both barrels and gallons. The exam wants to see if you have carefully noted this information rather than guessing based on partial memory.

Given Data / Assumptions:

• The passage states that the pipe is 4 feet in diameter.
• It also states that up to a certain number of barrels and gallons of crude oil can be pumped through it daily.
• The options express different quantities, some in gallons and some in barrels.
• We must select the quantity that exactly matches the passage.

Concept / Approach:
When answering numerical detail questions, it is important to match both the number and the unit. Even if more than one option appears close, only one will correctly reflect the value given in the text. The passage provides both barrels and gallons, and one of the options reproduces the gallon figure exactly, which is what this question emphasises.

Step-by-Step Solution:
Step 1: Recall the relevant line from the passage. It states that the pipe is 4 feet in diameter and that up to 2 million barrels (or 84 million gallons) of crude oil can be pumped through it daily.Step 2: Notice that the passage gives a barrel figure and then immediately translates it into gallons.Step 3: Examine the options. Option A mentions "2 million gallons", which is wrong because the passage says "2 million barrels", not gallons.Step 4: Option B mentions "4 million barrels", which does not match either quantity in the passage.Step 5: Option C mentions "84 million gallons of crude oil", which exactly matches the alternative capacity expression given in the passage.Step 6: Option D mentions "84 billion barrels", which is vastly different from the passage and clearly incorrect.Step 7: Therefore, option C must be the correct answer.

Verification / Alternative check:
Re reading the capacity statement confirms that the author used both numbers: 2 million barrels and 84 million gallons per day. These two figures represent the same quantity using different units. The exam question specifically offers options that mix numbers and units, so you must match the combination accurately. Only "84 million gallons of crude oil" reproduces one of the exact forms, confirming option C as correct.

Why Other Options Are Wrong:
Option A incorrectly mixes the number from the barrel figure with the gallon unit, producing "2 million gallons" instead of "2 million barrels" and thus does not match the passage.
Option B changes both the number and keeps barrels as the unit, but "4 million barrels" is never mentioned in the text.
Option D exaggerates the capacity enormously and uses the wrong unit and magnitude compared to the passage.

Common Pitfalls:
Many test takers misremember numbers or mix up units under time pressure, especially when the passage gives two equivalent quantities. A common error is to remember "2 million" but forget whether it refers to barrels or gallons. To avoid this, always link numbers and units together when reading and try to visualise or repeat the phrase in your own words immediately after reading it.

Final Answer:
The pipeline can carry up to 84 million gallons of crude oil daily, so the correct option is "84 million gallons of crude oil", option C.