Official Explanation
In this question, we want to compare two relationships, the relationship of Franklin to the younger members of the Continental Congress, such as Jefferson and Hancock, and the relationship of Bohr to the founders of Quantum Mechanics, such as Schrödinger and Heisenberg. Essentially, the sentence is saying that these two relationships were similar (older man providing a guiding example to a group of younger men). What’s the idiomatic way to say this in English?
(A) “had the same relationship” . . . “just like the relationship” This is awkward and unidiomatic.
(B) “had a relationship” . . . “the same as the relationship” This is awkward, redundant, and unidiomatic.
(C) This is the correct idiom for comparing relationships:
A is to X what B is to Y.
Choice (C) follows this idiom perfectly.
(D) This choice starts out very good, but it replaces the second half of the idiom with “just the same as Niels Bohr was to.” This sounds awkward, and its emphasis on “just the same” is a bit illogical.
(E) similar to (A), this is awkward and unidiomatic.
The best answer is (C).