For toxicological analysis, viscera are preserved in-
Actually, 10% sodium chloride is not a fully correct answer. Toxicological viscera is preserved in a saturated solution of common salt (sodium chloride). But this happens to be the closest answer.
For toxicological analysis, viscera is never preserved in alcohol, formalin, or bile salt. In fact, formalin denatures proteins and chemical toxins and would interfere with the detection of poisons during chemical analysis.
20% alcohol
10% formalin
10% sodium chloride
Common bile salt