Factors influencing the selection of optional subjects by UPSC aspirants include personal interest, academic background, and perceived scoring potential. Candidates often choose subjects they are passionate about or have expertise in, ensuring they can engage deeply with the material. Additionally, aspirants consider the availability of resources, like coaching and study materials, when making their choices. Some candidates also research past trends to identify which subjects yield higher scores. Ultimately, aligning one's strengths with possible scoring capabilities is a critical strategy for optimizing performance in the UPSC examinations.