What is an open reading frame?

A) the nucleotides between and including a start codon and an end codon in all chromosomes
B) the nucleotides between and including a start codon and an end codon, minus the introns
C) the nucleotides between and including a start codon and an end codon, minus the exons
D) the nucleotides between a start codon and end codon only in prokaryotes