Anaphase initiation in mitosis Steps:

• Anaphase begins with the separation of sister chromatids due to cohesin degradation.
• Separated chromatids move toward opposite poles as individual chromosomes.
• DNA stays associated with histone proteins throughout all mitotic phases.
• The plasma membrane (cell surface) remains intact during the entire process.

Why C is correct:

• It matches the definition of anaphase onset: sister chromatids separate, histones always bind DNA, and cell surface stays intact.

Why the others are wrong:

• A: Chromatids remain attached as chromosomes until anaphase starts; cell surface is not broken apart.
• B: DNA is in separated sister chromatid form, not intact chromosomes, at anaphase beginning.
• D: Histones always associate with DNA, not sometimes; cell surface remains intact, not broken apart.

Final answer: C