Based on Ivan's description that the juice is sweet and has a nice orange color, the most likely type of orange the juice is made from is:
A) Navel orange
Navel oranges are known for their sweetness and bright orange color, making them a common choice for juicing. Seville oranges are typically bitter, blood oranges have a darker color and a more unique flavor, and clementines are small and sweet but not typically used for juicing in larger quantities like navel oranges.