The electron micrograph illustrates a section of a plant cell (scale bar $5\,\mu\text{m}$). Which option correctly names the labelled cell structures P, Q, R and S?
- AP: cell surface membrane; Q: cytoplasm; R: mitochondrion; S: nucleus
- BP: cell surface membrane; Q: vacuole; R: chloroplast; S: nucleus
- CP: cell wall; Q: cytoplasm; R: mitochondrion; S: nucleolus
- DP: cell wall; Q: vacuole; R: chloroplast; S: nucleolus