Hi
The answer is:
Thiamine, Adenine, Guanine, Cytosine
These four are the nitrogenous bases that are integral components of the DNA molecule. These along with phosphates and deoxyribose sugar make up the DNA molecule. The Adenine always pairs with the Thiamine base, and the Guanine always pairs with the Cytosine base in a DNA molecule, through hydrogen bonds.
Hope this helps!