Answer:
Tree C
Explanation:
each of the charts/tables/paragraphs are talking about a different tree. 
Tree A started with 5 inches, as it says. 
Tree B started with 3 inches, as you can see under the 0 months. 
Tree C, at the month 0 mark, has a height of 10 inches, so it started with 10. 
10>5 and 10>4, so Tree C is the biggest