In agarose gel electrophoresis, how are DNA or RNA molecules typically visualized on the gel after separation?

• A. By staining the gel with a nucleic acid–binding dye (e.g., ethidium bromide or SYBR Safe) and viewing bands under UV or blue light
• B. By detecting radioactivity emitted spontaneously by DNA or RNA without any labeling or staining
• C. By adding DNA polymerase to the gel so it synthesizes complementary strands that become visible to the naked eye
• D. By measuring the temperature increase of the gel caused by nucleic acid migration and converting it into an image

Answer: (A)