Choose the word with the incorrect spelling:
a. Tactic
b. Tangible
c. Tacit
d. Tentitive

Hint: In the English language, words are not spelt the way they are pronounced. A word is only valid if it belongs to the lexicon or the vocabulary of the language.

Complete answer:
From the hint given to us, we know that in the English language, words are not spelt the way they are pronounced. A word is only valid if it belongs to the lexicon or the vocabulary of the language. Thus, we can infer that the incorrectly spelt word will not belong to the lexicon of the language and hence, will be meaningless in nature.
a. Tactic means an action plan or a strategy. It is a noun. We observe that it belongs to the lexicon of the language and thus, we can infer that the word is correctly spelt. Hence, option A is not the correct answer.
b. Tangible means being able to perceive by the sense of touch. It is an adjective. We observe that it belongs to the lexicon of the language and thus, we can infer that the word is correctly spelt. Hence, option B is not the correct answer.
c. Tacit means something that is understood without having been said aloud. It is an adjective. We observe that it belongs to the lexicon of the language and thus, we can infer that the word is correctly spelt. Hence, option D is not the correct answer.
d. Tentitive is an invalid word and meaningless in nature as it does not belong to the lexicon of the English language. Thus, we infer that it is an incorrectly spelt word. Hence, we can conclude that option D is the correct answer.

Note: Tentitive is the incorrect spelling of the word, tentative. Tentative means unconfirmed. It is an adjective.