Answer:
The correct answer will be option-A
Explanation:
Colchicine is the drug that prevents the assembly of the mitotic spindles which halts or stops the cell cycle.
The colchicine acts by inhibiting the microtubule polymerization thus mitotic spindles which takes place after the condensation of the chromosomes during prophase and pre-metaphase.
This acts as checkpoint which can halt the cell cycle at the phase of chromosome condensation.
Thus, option-A is the correct answer.
