She could always hide the fact that she was _________ until someone asked her to write her name or read a document.illiteratecausticemaciatedpretentious

The correct answer is "illiterate". The sentence implies that the woman is able to conceal a certain characteristic until she is asked to perform tasks such as writing her name or reading a document. Out of the given options, only "illiterate" fits this context. Being illiterate means not being able to read or write. The other options - caustic (sarcastic in a scathing and bitter way), emaciated (abnormally thin or weak, especially because of illness or a lack of food), and pretentious (attempting to impress by affecting greater importance or merit than is actually possessed) - do not fit the context.