All lights on cases

A building has n lights in a row, each on or off. This function checks whether they are all on. It returns as soon as it finds one that is off.

def all_on(lights):
    for light in lights:
        if not light:
            return False
    return True

public static boolean allOn(boolean[] lights) {
    for (boolean light : lights) {
        if (!light) {
            return false;
        }
    }
    return true;
}

(a) Describe the input of n lights that gives the best case. [1]

(b) Describe an input of n lights that gives the worst case. [1]

(c) A student writes: "The best case is when there are no lights, so the function is O(1)." Explain two things that are wrong with this claim. [2]

[4]