The board chair's annual (A) report was more (B) encouraging than any( C) annual report we have heard in the past five years (D).

Explanation

The sentence should read: "The board chair's annual report was more encouraging than any annual report we have heard in the past five years."The word "any" should be replaced with "the most" or "the best" to make the sentence grammatically correct and idiomatic.However, if we want to keep the word "any", the correct sentence would be: "The board chair's annual report was more encouraging than any other annual report we have heard in the past five years."