Which of the following is not a selective herbicide?

The choice that is not a selective herbicide is Paraquat. This is because Paraquat is classified as a non-selective herbicide, meaning it will kill most plants it comes in contact with, regardless of whether they are weeds or desirable plants. This broad-spectrum activity makes it effective for clearing areas of vegetation entirely.

In contrast, the other herbicides listed are selective. They are formulated to target specific plant species while leaving others unharmed. For instance, 2,4-D and Dicamba are both commonly used to control broadleaf weeds in grass crops. Garlon 3A, typically used for woody plants, is also selective, targeting certain species while preserving others nearby. Understanding the distinction between selective and non-selective herbicides is crucial for effective weed management and environmental protection.