A researcher gives the following options to a respondent while asking a question during a survey. Identify the options which suffer from ambiguity. Choose the correct answer from the options given below.

Very often, quite often and not very often are ambiguous because respondents interpret frequency vaguely and differently.

Very often lacks any fixed numeric anchor, so its meaning varies across people.

Quite often is equally imprecise, sitting somewhere undefined on a scale.

Not very often again gives no clear boundary for how rare the behaviour is.

Not at all is unambiguous because it clearly means zero occurrence.

Precise response scales should use defined intervals such as times per week.