Answer:
<em>The correct option is A. Nucleotide sequence, human, hemoglobin</em>
Explanation:
If the segment of the DNA for the human gene is known then it will be very easy to find the gene on a database. The tags which should be used will be the nucleotide sequence, where the known sequence shall be mentioned.
Then we will choose the tag for the organism which is humans in this case. Then we will select the tag for the protein which is made by the nucleotide sequence, which is protein in this case. Hence, option A is the correct answer.
