Answer:
correct option is a. Land
Step-by-step explanation:
given data 
land costing = $400,000 
subsidiary 2017 = $450,000 
land credit = $50,000 
 
solution 
While when we consolidating land that will appear in the group asset at the amount of 450,000. 
so here the appreciation in the value of land is not realized gain .
so that there will be credit to land with 50,000 
so correct option is a. Land