नील-हरित शैवाल (BGA) का उपयोग मुख्य रूप से किस फसल की खेती में जैव उर्वरक के रूप में किया जाता है?

Which of the following are characteristics/properties of biofertilizers? 1. They liberate plant growth-promoting substances and vitamins that maintain soil health. 2. Biological N2 fixers reduce soil nutrient depletion and promote sustainable farming. 3. They are non-renewable, expensive, and cause ecological pollution. 4. They improve soil tilth, structure, and physical health. Select the correct answer using the codes given below.

Which of the following is an example of a biofertilizer used in agriculture?