For a spindle to form in which chromosomes move along its microtubules, what cellular structure must dissolve during prophase and prometaphase?

Nuclear membrane/envelope

Explanation:

Mitosis, as one type of cellular division, occurs in five stages; Prophase, prometaphase, Metaphase, Anaphase and Telophase. After the cell must have prepared itself to enter this division process by enlarging and forming duplicate of its genetic material and organnelles in the Interphase stage, it starts Prophase.

In the Prophase, condensation of chromosomes occur and centrosomes move towards opposite poles to produce spindle microtubules that will later pull the chromosomes apart. In the prometaphase stage, the envelope that bounds the DNA in the nucleus is degraded in order for the growing microtubules to have direct access of attachment to the chromosomes.

the answers are a and c