Which of the following is used to make artificial eyelashes adhere to the natural lash line?

Lash adhesive is specifically formulated for the safe and effective application of artificial eyelashes. Unlike general glues or adhesives, lash adhesives are designed to bond with both false lashes and the delicate skin of the eyelids without causing irritation. They often contain ingredients that minimize the risk of allergic reactions and are tested for ophthalmological safety, making them suitable for use near the eyes.

While other types of adhesives may have similar bonding properties, they are not intended for use on skin or eyes and may contain harsh chemicals that could lead to irritation or damaging the natural lashes. Watersafe adhesive and contact adhesive, while used in different contexts, do not have the specialized formulation that lash adhesives possess for this particular application. Thus, lash adhesive is the optimal choice for ensuring that artificial eyelashes adhere securely and safely to the natural lash line.