Answer:
The correct option is B) the set of all first elements of the function.
Step-by-step explanation:
Consider the provided information.
Domain: Domain is the set of all values which a function can take or the domain is the set of all first elements of ordered pairs.
For example:
The domain of the polynomial function is the set of all real numbers.
Consider the another example:
A = {(green,mark), (yellow,Kyle), (blue,Elaine)}
The domain is {green,yellow,blue}
Therefore, the correct option is B) the set of all first elements of the function.