The value of `(.^(21)C_(1) - .^(10)C_(1)) + (.^(21)C_(2) - .^(10)C_(2)) + (.^(21)C_(3) - .^(10)C_(3)) + (.^(21)C_(4) - .^(10)C_(4)) + … + (.^(21)C_(10) - .^(10)C_(10))` is (A) `2^(21) - 2^(11)` (B) `2^(21) - 2^(10)` (C) `2^(20) - 2^(9)` (D) `2^(20) - 2^(10)`