This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to cook with a convection toaster oven
Know what a convection oven is.
A traditional oven has heating elements on top and bottom of the oven. A convection oven differs by having a fan in addition to the heating elements.

Choices: [I] The heat generated by the heating element sucks out the bad smells from the air. Thus, convection oven items are deviled by strong odors. [II] The fan continuously circulates air through the oven as the food cooks. This process of blowing hot air over the food as it cooks makes the food cook more evenly. [III] Try cooking with a convection oven in a lower degree setting (10 degree). These ovens are more difficult to use than a traditional oven with a fan, but they are arguably easier on your body. [IV] A convection oven had two heat elements: a indoor convection stove and a portable invert oven. The air inside the convection oven heats the air in the convection oven's broiler to a temperature of 178 degrees fahrenheit (10 degrees celsius).
The answer is:
[II]