A vertical glass capillary tube, open at both ends, contains some water. Which of the following shapes may be taken by the water in the tube ?

The pressure of the air and the water inside are not equal in the higher half. There is more pressure in the atmosphere. Water adopts a concave shape as a result and seeks to anticipate the downward force brought on by too much pressure.

The force resulting from air pressure is equal to the components of surface tension along the upward direction. The difference between atmospheric pressure and the pressure inside the water is known as excess pressure. Water hence has a concave upper surface.

Both the weight of the water and the air pressure exert a force downward on the bottom side. The sea surface is convex to anticipate this high force (when looked from the outside). In this manner, the upward components of surface tension are equivalent to the net downward force. This end is convex from the outside as a result.

Hence the correct answer is option D.