Teacher:In this task, you're given a question, along with a context passage which has extra information available on certain terms mentioned in it. Your job is to determine which sentence(s) from the passage can be used to search for further information needed to answer the question.
Teacher: Now, understand the problem? Solve this instance: Question: Who was older when Heitler obtained his doctorate, Arnold Sommerfeld or Karl Herzfeld? Passage:In 1922, Heitler began his study of physics at the Karlsruhe Technische Hochschule, in 1923 at the Humboldt University of Berlin, and in 1924 at the Ludwig Maximilian University of Munich (LMU), where he studied under both Arnold Sommerfeld and Karl Herzfeld. The latter was his thesis advisor when he obtained his doctorate in 1926; Herzfeld taught courses in theoretical physics and one in physical chemistry, and in Sommerfeld's absence often took over his classes. From 1926 to 1927, he was a Rockefeller Foundation Fellow for postgraduate research with Niels Bohr at the Institute for Theoretical Physics at the University of Copenhagen and with Erwin Schrodinger at the University of Zurich. He then became an assistant to Max Born at the Institute for Theoretical Physics at the University of Gottingen. Heitler completed his Habilitation, under Born, in 1929, and then remained as a Privatdozent until 1933. In that year, he was let go by the university because he was Jewish.

Student:
The latter was his thesis advisor when he obtained his doctorate in 1926; Herzfeld taught courses in theoretical physics and one in physical chemistry, and in Sommerfeld's absence often took over his classes