Answer:
The correct answer is b. an amino acid
Step-by-step explanation:
A tRNA is called adaptor RNA which have cloverleaf-like secondary structures. These structures contain stems and loops which make up the acceptor arm, anticodon stem and loop, D- stem and loop, and T- stem and loop.
Acceptor arm contains seven base pairs and four single stranded nucleotide which include conserved CCA sequence. The function of acceptor arm is attach amino acids require for protein synthesis.
The anticodon loop gives information to acceptor to attach a specific amino acid according to the sequence present in mRNA. The first amino acid which attaches to acceptor arm is methionine.
Thus, the correct answer is b. an amino acid.