Final answer:
Merkel endings, known as Merkel discs, are unencapsulated mechanoreceptors responsible for light touch, especially in areas like fingertips and lips. Meissner's corpuscles and Pacinian corpuscles are other forms of mechanoreceptors that respond to light and deeper touch, respectively.
Step-by-step explanation:
Merkel endings are also known as B) Merkel discs. These are a type of mechanoreceptor found in the skin that are responsible for the sense of light touch, especially important in areas such as the fingertips and lips. Contrary to some types of mechanoreceptors, Merkel discs are unencapsulated and respond to light pressure, allowing us to detect fine details through touch.
Some other mechanoreceptors include Meissner's corpuscles, which are encapsulated and also respond to light touch and low-frequency vibration and are found more superficially in the skin. Pacinian corpuscles, on the other hand, are encapsulated and detect transient pressure and high-frequency vibration; they are found deeper in the skin. Ruffini endings are encapsulated as well and detect stretch, deformation within joints, and warmth.