To solve this problem, we need to identify the method used to visualize separated DNA fragments in gel electrophoresis. Let's analyze the options:$\newline \bullet$Option 1: Ethidium bromide in UV radiation$\newline$ - Ethidium bromide is a fluorescent dye that intercalates between DNA bases.$\newline$ - When exposed to UV light, it fluoresces, allowing visualization of DNA bands.$\newline$ - This is a common method used in laboratories for visualizing DNA.$\newline \bullet$Option 2: Acetocarmine in UV radiation$\newline$ - Acetocarmine is a stain used for chromosomes in plant cells, not for DNA in gel electrophoresis.$\newline$ - It does not fluoresce under UV light.$\newline \bullet$Option 3: Ethidium bromide in infrared radiation$\newline$ - Ethidium bromide requires UV light to fluoresce, not infrared radiation.$\newline \bullet$Option 4: Acetocarmine in bright blue light$\newline$ - As mentioned, acetocarmine is not used for DNA visualization in gel electrophoresis.$\newline$ - Bright blue light is not suitable for visualizing DNA with acetocarmine.$\newline$Based on the analysis, the correct method for visualizing DNA fragments in gel electrophoresis is:$\newline$Option 1: Ethidium bromide in UV radiation.$\newline$Therefore, the correct option is Option 1.