If the sequence of nitrogen bases of the coding strand of DNA in a transcription unit is: 5' - A T G A A T G - 3', the sequence of bases in its RNA transcript would be;
a. 5' - A U G A A U G - 3'
b. 5' - U A C U U A C - 3'
c. 5' - C A U U C A U - 3'
d. 5' - G U A A G U A - 3'