Here's a problem to solve: Birds come in a variety of colors, shapes, and sizes. Which usually determines the color, shape, and size of a bird?

Among the 4 following options, which is the correct answer?

- A: the time of year it was born
 
- B: the type of food the bird eats
 
- C: the bird's migratory patterns
 
- D: what the bird inherited from its parents
 