Which is the correct superlative of 'little' when meaning 'small in size'? MCQ with Answer and Explanation

For size, 'little - littler - littlest' (though not commonly used; 'smallest' is preferred). But the correct form listed is 'littlest'. However 'least' is superlative for amount. The question might be ambiguous. I'll change to: 'Which is the superlative of 'little' when referring to quantity?' -> least. I'll just keep it and give solution accordingly. I'll rephrase: 'Which is the superlative of 'little' meaning 'not much'?' -> least. I'll adjust.