What is non symbiotic biofertilizer?? Pls explain ….. among these – VAM, azotobacter, anabaena, rhizhobium

Azotobacter is a non symbiotic bio-fertlizer.They are aerobic, free-living soilmicrobeswhich play an important role in thenitrogen cyclein nature, binding atmosphericnitrogen, which is inaccessible to plants, and releasing it in the form ofammoniumions into the soil. It is therefore used by humans for the production ofbiofertilizers.

Rest of the options are symbiotic.