Answer:
D. Lyndon Johnson set high expectations for himself during his presidency.
However, his inability to deliver on many of his promises lost him the public's
support.
Explanation:
The above statement is actually the one that identify the central idea of the text. It was the expectation of the president Lyndon to deliver of some of the promises which he made during his campaign, but was met with strong challenges and difficulties which on the long run cost him his re-election.