The ribosomes responsible for protein synthesis are present in the cell _.

Explanation

Ribosomes are essential organelles for protein synthesis and exist in two primary forms within the cell. Free ribosomes float in the cytosol and are responsible for synthesizing proteins that will function within the cytosol. In contrast, ribosomes bound to the rough endoplasmic reticulum (RER) typically synthesize proteins destined for secretion or incorporation into cellular membranes. Therefore, the correct answer is that ribosomes are present both floating in the cytosol and bound to the rough endoplasmic reticulum.Option A is incorrect because while ribosomes do float in the cytosol, this answer does not account for the ribosomes on the RER. Option B is incorrect because ribosomes are not active in protein synthesis within the nucleus. Option C is incorrect because while ribosomes are bound to the RER, this answer does not account for those that float freely in the cytosol.