Correct Answer: K > Zn > Cu > Ag
Subject: 2025
Explanation: <b>Key Fact</b><br>In the electrochemical reactivity series: Potassium (K) is highly reactive, followed by Zinc (Zn), then Copper (Cu), and Silver (Ag) is the least reactive.<br><br><b>Additional Info</b><br>Topic: Metal Reactivity Series.<br><br><b>Why the other options are wrong</b><br>Option A: Correct.<br>Option B: Incorrect because Zinc is more reactive than Copper.<br>Option C: This represents an increasing order of reactivity, not decreasing.<br>Option D: Incorrect order.<br><br><b>Exam Trick</b><br>Mnemonic: 'Please Stop Calling Me A Careless Zebra Instead Try Learning How Copper Saves Gold'.<br><br><b>Final Answer</b><br>Option A — K > Zn > Cu > Ag.