Which of the following is a key characteristic of extra virgin olive oil?

Extra virgin olive oil is primarily defined by its production method, which includes the process of first cold pressing. This means that the olives are pressed for the first time without the use of heat or chemicals, ensuring that the oil retains its natural flavors, aroma, and health benefits. The lower temperature helps to preserve the oil's high levels of antioxidants and polyphenols, which are responsible for its health-promoting properties.

Additionally, extra virgin olive oil must meet strict quality standards, including low levels of acidity, which indicates a careful and high-quality extraction process. It is noted for its robust flavor profile, characterized by distinct grassy, fruity, or peppery notes, as opposed to being lightly flavored. This richness in taste is a result of the pressing process and the quality of olives used, which are typically harvested at their peak ripeness.

The other options do not accurately reflect the characteristics of extra virgin olive oil, as refined oil goes through a process that depletes much of its taste and nutrients, lightly flavored does not describe the bold taste typical of this oil, and heated extraction alters the quality and health properties that define extra virgin olive oil.