Step 1: Analyze differences — 9−4=5, 19−9=10, 34−19=15, 54−34=20 → Pattern: +5, +10, +15, +20 → Next difference = 25
Step 2: Compute next term — 54 + 25 = 79 → Wait check options: 79 exists (c). Correction: 54 + 20 = 74? 34→54 = +20, next +25 → 54+25=79
Step 3: Conclusion — Option (c) 79 is correct.