Design a concise experimental approach (choose the best combination) to demonstrate differential gene expression between cultured muscle and neural cells, indicating the measurement method and expected outcome. Use experimental-design synthesis.

• A. Measure total protein concentration per cell and conclude that the type with more total protein is the specialized one, without identifying specific gene products.
• B. Isolate mRNA from each cell type and perform quantitative RT-PCR or RNA sequencing for marker genes; expect high expression of muscle-specific genes in muscle cells and high expression of neuron-specific genes in neural cells.
• C. Use light microscopy only to observe cell shape and state that morphological differences alone prove differential gene expression without molecular assays.
• D. Sequence the entire genome of both cell types and compare DNA sequences expecting many differences that correspond to their functions.

Answer: (B)