Answer: Option 'C' is correct.
Step-by-step explanation:
convex mirror is used to look under a vehicle during a security check because it provides a wider field of view and the images formed are virtual but smaller and upright.
As the image of convex mirror provides rear view in a small frame.
i.e. the images formed by convex mirror are virtual and as it covers wider range, the image is smaller than real but upright.
Hence, option 'C' is correct.