A.possessive
B.noun clause
C.adjective clause
D.adverb clause
Ardent means very enthusiastic or passionate, we can feel in this passage that the children’s feeling was very strong, is says that “they were about to fall out of the open door” these kids were kind of desperate until they saw their father, the best word to replace ardent in this case would be powerful based in the actual meaning of the word and the context were it is being used.