Choose the option that best completes the gap: The _______ of the accused was established beyond reasonable doubt by the prosecution.

'Guilt' is the correct noun form meaning the fact of having committed a specified offence. 'Guiltiness' is a non-standard form, 'guiltful' is not a recognised English word, and 'guilting' is a gerund/present participle that does not fit the syntactic role required here.