Final answer:
Pyknosis refers to the condensation of the cell nucleus, typically observed in cells undergoing necrosis or apoptosis. Option b is correct.
Step-by-step explanation:
Pyknosis indicates a condensed cell nucleus. This term is used to describe the morphological changes that occur in the nucleus of a cell undergoing necrosis or apoptosis, where the nucleus shrinks and the chromatin condenses.
It does not describe neutrophils with multiple lobes, which are referred to as polymorphonuclear due to their lobed appearance, nor does it refer to toxic changes in lymphocytes and neutrophils or cells with lysed or damaged nuclei specifically.