Thinking about why the law would fix any deadline at all for this application helps confirm which of the four numbers is correct.
Since the statutory deadline is designed to secure a prompt decision without being unreasonably short, the number that matches both this design and the actual text of the BNSS is 15 days, which is the correct answer.
Because criminal procedure contains several different day-based deadlines for different purposes, it helps to make sure this particular number is not being confused with a different, unrelated timeline.
Keeping this deadline distinct from other, differently numbered timelines used elsewhere in criminal procedure confirms that the period fixed specifically for a plea bargaining application under the BNSS is 15 days from the framing of charges, which is the correct answer.