6437. The drugs were innocuous and had no side effect.

✅ The correct answer is option B.
Effective : successful in producing a desired or intended result.

Harmless : not able or likely to cause harm.

Imported : (of goods or services) brought into a country from abroad for sale.

Discovered : find unexpectedly or during a search.

Innocuous : not harmful or offensive.

Synonym of Innocuous is Harmless