10² + 5².

**The reasoning** This tests **order of operations** (BODMAS/PEMDAS) and basic squaring. Break it down step by step: - 10² means 10 × 10 = **100** - 5² means 5 × 5 = **25** - Now add them: 100 + 25 = **125** The key principle: Handle each square **separately first**, then add. Don't try to add 10 + 5 before squaring! **Why the wrong options tempt you** **A) 75** — You might have done (10 + 5) × 5 = 75, mixing operations incorrectly. **C) 150** — Perhaps you did 10² + 5 × 10, forgetting to square the 5. **D) 200** — This looks like (10 + 5)² which would be 15² = 225... or you doubled something by mistake. The trap is **rushing and combining numbers before completing the squaring**. **Quick takeaway** **"Square each number separately, THEN add the results"** — never combine numbers inside brackets unless the question shows them there!