Definition: From the given sentence, extract the phrase (often noun or verb) that carries the given relationship. The generated phrase should be present in the sentence.
Input: Given Relationship: 'be son of', Sentence: 'Dasaratha is the eldest son of Aja , and his four sons , a precious jewel each one , are Rama , Lakshmana , Bharatha and Satrughna .'
Output:
son