• To find the correct spelling let us first we need to focus on the phonetics sounds. Phonetics refers to the knowledge of words or sounds of a specific  language.
• Inevitable is a word which is correctly 
• Inevitable means a thing or person which is unavoidable.
• Ineventable-  The sound of the inevitable is different from the sound of the ineventable.
• Inventable- The sound of the inevitable is different from the sound of the inventable.
• Invitable- The sound of the inevitable is different from the sound of the invitable.

Hence, option A is the correct answer.