This cell lacks cytoskeleton

The correct option is "prokaryotic bacterial cells".

To understand why prokaryotic bacterial cells lack a cytoskeleton in the classical sense, we can break down the differences in cellular structure between prokaryotes and eukaryotes:

1. Eukaryotic Cells and the Cytoskeleton:
Eukaryotic cells (which include both plant and animal cells) possess a highly developed, complex network of protein filaments and tubules within their cytoplasm. This network is known as the cytoskeleton. It consists of three primary types of fibers: microfilaments (actin filaments), intermediate filaments, and microtubules (tubulin). This system is responsible for maintaining cell shape, enabling cell movement, facilitating intracellular transport, and aiding in cell division.

2. Prokaryotic Cells (Bacterial Cells):
Prokaryotic bacterial cells are structurally much simpler and smaller than eukaryotic cells. Historically, they were described as lacking a cytoskeleton because they do not contain the classical, membrane-anchored eukaryotic microfilaments, intermediate filaments, or microtubules. While modern research has identified prokaryotic homologues (proteins similar to actin and tubulin, such as MreB and FtsZ), classical biology textbooks and curricula define prokaryotes as lacking the true, complex eukaryotic cytoskeleton.

Conclusion:
Since eukaryotic plant cells and eukaryotic animal cells contain a well-defined, complex cytoskeleton, the only group among the choices that lacks this classical eukaryotic cytostructural network is the prokaryotic bacterial cells.