Dyad is a pair of

Dyad is a word derived from the Greek word ‘dyas’ meaning two.

Dyad is a pair of sister chromatids that occur in prophase I of meiosis.

The two sister chromatids are joined as a common point called the kinetochore.

The figure below shows the diagrammatic representation of a dyad.

Hence the correct answer is A, that is a pair of sister chromatids.