The technique of communication by signs made with the fingers. It is generally used by the deaf :

Step-by-step solution

Dactylography - the impression on a surface of the curves formed by the ridges on a fingertip. Dactylogy - The use of the fingers and hands to communicate ideas, especially by the deaf. Chromatics - the branch of colorimetry that deals with hue and saturation. Eugenics - the practice or advocacy of improving the human species by selectively mating people with specific desirable hereditary traits. Hence, the correct answer is option B.