What physical characteristic does a retinal scan biometric device measure?视网膜扫描设备检测哪些人体物理特性？（）

• A、The pattern of light receptors at the back of the eye眼底光受体组织的图案
• B、The pattern of blood vessels at the back of the eye眼底血管的图案
• C、The amount of light reaching the retina视网膜受光量