77. Why is there a concern about copper smelting plants? (1) They may release lethal quantities of carbon monoxide into environment. (2) The copper slag can cause the leaching of some heavy metals into environment. (3) They may release sulphur dioxide as a pollutant. Select the correct answer using the code given below: (a) 1 and 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3

Click on the right option
1) 1 and 2 only
2) 2 and 3 only ✅
3) 1 and 3 only
a) 1, 2 and 3