In the sentence below, the introductory modifying phrase is underlined. Choose the option that correctly completes the sentence by ensuring the modifier logically describes the correct subject. Type the letter of the correct option (A, B, C, or D) in the blank.
Sentence:
Though designated as a sanctuary for endangered shorebirds, {{blank_1}}.
Options:
A. the environmental agency's new regulations only protected the northern spit of the barrier island
B. the environmental agency only protected the northern spit of the barrier island with new regulations
C. the northern spit of the barrier island was the only area protected by the environmental agency's new regulations
D. protecting the northern spit of the barrier island was the sole focus of the environmental agency's new regulations