The correct option is A Monosaccharide
Carbohydrates are classified based on number of monomers obtained after hydrolysis as follows:
(i) Monosaccharides (no further hydrolysis)
(ii) Disaccharides (gives two monomers on hydrolysis)
(iii) Trisaccharides (gives three monomers on hydrolysis)
(iv) Oligosaccharides (gives 3−10 monomers on hydrolysis)
(v) Polysaccharides (gives more than 10 monomers on hydrolysis)
Monosaccharides: Simplest form of carbohydrate which can not be hydrolysed further. They have general formula(CH2O)n.
Hence, (a) is correct.