Concept:Subsistence farming focuses on growing food for the farmer’s own family, so several crops are usually grown together to ensure food availability.Explanation:Subsistence farmers face the risk of crop failure and need a steady food supply.Growing more than one crop on the same land at the same time is called mixed cropping.Mixed cropping provides dietary variety and reduces the chance of total loss if one crop fails.Therefore, subsistence farmers mostly practice mixed cropping rather than growing only one crop or rotating crops.Answer:C. Mixed cropping