Candidates may change their optional subjects before the exam due to several reasons. First, they might find the initially chosen subject challenging or less engaging, resulting in inadequate preparation. Second, feedback from peers or mentors could highlight better prospects in another subject. Third, a candidate may discover that a different subject aligns more closely with their strengths, interests, or scores in prior examinations. Lastly, changes in the syllabus or exam patterns might prompt reassessment of the selected optional subject.