The meniscus formed by mercury in a test tube is : 

A meniscus can move up or down. Everything depends on whether the molecules of the liquid are more drawn to the material outside or to the liquid itself. Cohesion and adhesion are cited as the explanation for this.
When liquid molecules are pulled to those in the vessel, as is typically observed, a concave meniscus forms. It takes place using water and a glass tube. Similar to mercury and glass, molecules have a stronger attraction to one another than to the container, which results in a convex meniscus. When water is introduced into specific kinds of plastic tubes—tubes manufactured from different materials that water doesn't adhere to—a flat meniscus forms.

In any case, you may determine the liquid's actual volume by measuring the liquid's center in the tube.
As a result, when water is put into a glass bottle, surface tension causes the water molecules to adhere to the glass's sides. As adhesion then overcomes the forces that hold the molecules together, the water slowly climbs the container. Mercury is an exception to this rule since the opposite occurs with water. It is adhesion when cohesion forces are stronger than the glazing attraction. It produces the opposite result, making it convex.

Hence, the correct answer is option A.