Imagine looking through a microscope at a squashed onion root tip. The chromosomes of many of the cells are plainly visible. In some cells, replicated chromosomes are aligned along the center (equator) of the cell.
These particular cells are in which stage of mitosis?

A) telophase
B) prophase
C) anaphase
D) metaphase
E) prometaphase

D) metaphase

Explanation:

Mitosis is a type of cell division in which the cell divides its replicated chromosome in equal amount in two daughter cells. Mitosis takes place in four phases: Prophase, Metaphase, Anaphase and Telophase.

Metaphase is the stage of the cell division during which the chromosome is present in the highly condensed form present in the centre of the cell. The chromosomes are aligned at the equator of the cell.

Thus, metaphase is the correct answer.

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.