The correct spelling of the word is "conscientious." It means "careful and thorough in one's work or actions."
The other options are incorrect spellings of the word. "Consceintious" is a misspelling that is often used, but it is not the correct spelling. "Conscintious" is another misspelling that is sometimes used, but it is also not the correct spelling. "Conscientious" is the correct spelling of the word.
