Which of the following statements is correct about the C#.NET code snippet given below?

int a = 10; 
int b = 20; 
int c = 30;
enum color: byte
{
    red = a, 
    green = b,
    blue = c 
}

class Sample
{
    public int func(int i, Single j)
    {
        /* Add code here. */
    }
}

1. A struct can contain properties.
2. A struct can contain constructors.
3. A struct can contain protected data members.
4. A struct cannot contain methods.
5. A struct cannot contain constants.

1. An attribute can be inspected at link-time.
2. An attribute can be inspected at compile-time.
3. An attribute can be inspected at run-time.
4. An attribute can be inspected at design-time.

1. A class
2. A property
3. A struct
4. A function
5. An interface