A combination of a ribose molecule, a thymine and a sugar molecule will form a 

Each nucleotide consists of a phosphate group, a nitrogenous base, and a pentose sugar molecule. Adenine, thymine, guanine, cytosine, and uracil are bases while ribose and deoxyribose are the pentose sugars. A combination of ribose, thymine and phosphate moiety forms a nucleotide. 

So, the correct answer is option B.