The number of chromatids in a chromosome at anaphase is

(b) The fourth phase of mitosis is anaphase, it is the process, which separates the duplicated genetic material carried in the parent cell’s nucleus into two daughter cells.
At the initiation of anaphase, the replicated chromosomes known as sister chromatids are amended along the equator of the cell on the central plane.
The sister chromatids are connected at a point known as the centromere.
Meiosis takes place in two stages, that is, meiosis I and meiosis II.
The homologous chromosomes separate and the number of chromosomes in daughter cells gets reduced to half in meiosis I, this is called reductional division.
On the other hand, in meiosis II, the splitting of centromere takes place and the chromosome number stays similar in the daughter cells, thus, it is an equational division.
Thus, the number of chromatids in a chromosome at anaphase is 1 in mitosis and 2 in meiosis.