Answer:
D. Most of the offspring plants will have purple stems, but some will have green stems.
Step-by-step explanation:
These plants are heterozygous, which means that they have two different alleles of the same gene. One allele, the ANL one, is going to dominate over the other resulting in purple-stemmed plants, which is the color that ANL encodes for.
If we draw a Punnet Square, we can see that the majority of the offsprings will have purple stems, but some of them, the ones that have two recessive alleles, will have green stems.
║ ANL ║ anl
ANL║ANL ANL ║ ANL anl
anl ║anl ANL ║anl anl