The gross profit margin for Amazon for each year from 2010 to 2012 is listed as follows.

• 2010: 22.35%
• 2011: 22.44%
• 2012: 24.75%

Which of the following statements is a reasonable explanation for the trend in the ratio?

Increased competition is forcing Amazon to lower its prices.

Amazon issued new stock during the year to raise additional capital.

Inventory prices have fallen resulting in decreased COGS.

Please help confirm my answer and explain it. Thanks!