Answer:
A. a double
Explanation:
The syntax of the function is:
type name( argument_1, argument_1,...... )
{
statement;
}
In the above syntax "type" define the return type of the function.
for example:
int count( int n);
so, it return the integer. Because the return type is 'int'.
In the question,
double compute speed(double distance);
Here, the return type is double. So, it return double.