Answer:
Option B
Step-by-step explanation:
Given , 
there is incomplete dominance of allele T and t when they pair together. Thus, TT genotype individuals are tall, Tt genotype individuals are medium heighted and tt genotype individuals are short. 
Total number of plants 

Number of short plants with genotype tt 

If the given population is in HW equilibrium, then as per the 1st equilibrium rule of HW

where p is the frequency of dominant allele and q is the frequency of 
recessive allele.
Here
 


Frequency of tall individuals with genotype "TT"

Hence, option B is correct