The approximate LD50 of the least toxic substance will be 130 mg/Kg.
The dose necessary to cause the death of 50% of a population under test after a predetermined test period is known as the LD50 value for a drug.
Commonly used as a broad indicator of a substance's acute toxicity are LD50 values.
Greater toxicity is indicated by a lower LD50. A low LD50 of 500 mg/kg or less implies severe toxicity.
Moderate toxicity is indicated by an LD50 of 500 to 1,000 mg/kg. A modest toxicity level of 1,000 to 2,000 mg/kg is indicated.
The species is especially vulnerable to the poison if the LD50 is low. The lethal dose (LD50) of a specific poison might change significantly between several animal species.
Thus out of all the options, LD50 130 mg/kg will have the lowest toxicity and 20 mg/kg will be the highest.
learn more about LD50 here: https://brainly.com/question/24845532
