एका प्रतलात 8 बिंदू आहेत, त्यातील कोणतेही तीन बिंदू एकरेषीय नाहीत. एका वेळी दोन बिंदूना जोडणाऱ्या रेषा काढल्या, तर अशा किती रेषा काढता येतील ?

Option D is the right choice since With 8 points, no three collinear, lines = ⁸C₂ = 8×7/2 = 28. Answers 25, 27, or 29 reflect off-by-one combination errors or wrongly subtracting diagonals when none are collinear. Distractors A (25), B (29), C (27) look plausible but do not follow from the facts stated in the question. Keep the name, formula, and unit together in your notes — that helps you spot incomplete distractors quickly.