Fastidious means having high standards and giving too much attention to small details to make something perfect. E.g. The restaurant offers amazing food and fastidious service at high prices. 'Faint' means feeling weak and dizzy. 'Delicious' means tasty. 'Dormant' means not active. 'Demanding' means to make others work hard or meet high standards. Thus, option B is the correct synonym for the given word. Rest of the options are incorrect.