Answer:
b) a smaller phenotype than others
Step-by-step explanation:
In the above scenario, Largene is a protein which is a transcription factor bind to promoter to increase the expression of lrgX gene and ultimately translateed the largeX protein which will help in the growth of body during adolescence.
So, if there will be low level of expression of largene than normal, it will not bind to promoter effectively or the largeXase can change the conformation of largene which will directly affect the promoter region because promoter will not activate more due to lower level of largene and at the result there will be very low level of expression of lrgX gene. Then largeX protein will be low and it will definitely affect the growth of body during puberty. The growth will be slower than other normal persons.
So, smaller phenotype will be observed than other normal ones.