**Option A — 3-year @ $3,800/mo flat:** $136,800 total, more flexibility. **Option B — 5-year @ $3,400/mo +4%/yr:** rises to ≈$3,977 by year 5, ≈$221,000 over 5 years (avg ≈$3,683/mo). **Takeaway:** B is cheaper per month early and locks your rate, but the escalator overtakes A's flat rate around year 4. Staying 5+ years → B. Any chance you move in 2–3 years → A's flexibility is worth the small premium.