The goal is to request politely while being concise.
Option (A) is polite but wordy, with unnecessary “very much” and “be kind enough” phrases that do not add meaning.
Option (C) is slightly shorter than (A) but still keeps the redundant “very much” and “kindly,” making it longer than needed.
Option (D) is the longest and most repetitive, combining “grateful” and “very much obliged,” which convey similar meanings.
Option (B) is direct and polite — “I should be much obliged if you could send me the required material” is both clear and concise without unnecessary modifiers.