Final answer:
Cosmetic products such as creams, lotions, masks, and makeup must include a manufacturer's label with important information. They should not be shared for hygiene reasons, and while some might benefit from refrigeration or expire after one year, these conditions vary by product.
Step-by-step explanation:
The answer to the question about creams, lotions, masks, and makeup is C) Must have the manufacturer's label. Every cosmetic product should have a label from the manufacturer that includes information such as ingredients, usage instructions, expiration date, and any warnings or precautions. Sharing these products among clients is not advised due to hygiene and health concerns, and while products do expire, the timeframe differs depending on the product. Some may last longer than a year if unopened or stored properly. Refrigeration is not universally necessary for all products, but may be recommended for some natural or organic products to extend their shelf life. It is crucial to follow the specific storage instructions indicated on each product's label.