Find out that word, the spelling of which is wrong.

Inocuous
Intellectual
Invertebrate
Irruption

The correct answer is C. Invertebrate.

The word “invertebrate” is spelled correctly. It is an adjective that means “having no backbone.”

The word “inocuous” is spelled correctly. It is an adjective that means “not harmful.”

The word “intellectual” is spelled correctly. It is an adjective that means “of or relating to the intellect.”

The word “irruption” is spelled correctly. It is a noun that means “a sudden and violent invasion or outbreak.”