Answer:
Chromatid
Step-by-step explanation:
The chromosome is a (sort of) X shaped structure. A chromatid represents half of this structure, i.e. one "strand" of the structure.
A centromere is the point at which to sister chromatids are connected to form a single chromosome. The centromere is also where the spindle attaches to move chromosomes during mitosis
A vaculole is a plant cell-specific organelle involved in the storage of water and nutrients.