The sequence of nucleotides in a messenger RNA molecule (mRNA) is determined by the sequence of nucleotides in a a transfer RNA (tRNA) molecule. b protein molecule. c polysaccharide molecule. d DNA molecule.

D-DNA molecule

Explanation:

The process of copying the sequence of DNA nucleotide sequences to the mRNA is called Transcriptions. It is the first stage in gene expression for protein synthesis, and it involves the unwinding of the DNA double strands molecules by enzyme DNA Helicase into two free strands, (by melting the hydrogen bonds between organic bases), a process initiated by the binding of enzymes RNA Polymerase to the promoter sites on the DNA template; the alignment of the mRNA nucleotides on the single DNA template strands in 3'-5 direction; the formation of hydrogen bonds between the organic bases of the template DNA and that of the messenger RNA single strands, (and phosphodiesterbonds within RNA nucleotide), to form DNA-RNA complex.

The copying is done in complimentary anti parallel fashion; 5'-3' prime. direction.

The hydrogen bonds, between the bases DNA-RNA complexes breaks, and the releases the mRNA which exists through the nuclear pores. Thus this leads to copying of the the coded messages as seqeunce of DNA, from the DNA to the mRNA for gene expressions.