Passage: Oppenheimer was awarded a United States National Research Council fellowship to the California Institute of Technology (Caltech) in September 1927. Bridgman also wanted him at Harvard, so a compromise was reached whereby he split his fellowship for the 1927–28 academic year between Harvard in 1927 and Caltech in 1928. At Caltech he struck up a close friendship with Linus Pauling, and they planned to mount a joint attack on the nature of the chemical bond, a field in which Pauling was a pioneer, with Oppenheimer supplying the mathematics and Pauling interpreting the results. Both the collaboration and their friendship were nipped in the bud when Pauling began to suspect Oppenheimer of becoming too close to his wife, Ava Helen Pauling. Once, when Pauling was at work, Oppenheimer had arrived at their home and invited Ava Helen to join him on a tryst in Mexico.  Though she refused and reported the incident to her husband, the invitation, and her apparent nonchalance about it, disquieted Pauling and he ended his relationship with Oppenheimer. Oppenheimer later invited him to become head of the Chemistry Division of the Manhattan Project, but Pauling refused, saying he was a pacifist.In the autumn of 1928, Oppenheimer visited Paul Ehrenfest's institute at the University of Leiden, the Netherlands, where he impressed by giving lectures in Dutch, despite having little experience with the language. There he was given the nickname of Opje, later anglicized by his students as "Oppie". From Leiden he continued on to the Swiss Federal Institute of Technology (ETH) in Zurich to work with Wolfgang Pauli on quantum mechanics and the continuous spectrum. Oppenheimer respected and liked Pauli and may have emulated his personal style as well as his critical approach to problems.

Question: Which institution awarded Oppenheimer a fellowship?
California Institute of Technology