Which sentence is missing a necessary comma after the word in bold?

A. (Sentence 6) Turning away from the ship’s compass, Captain Steele looked at Lovett with narrowed eyes but made no reply.
B. (Sentence 4) With the message burned into his mind, First Mate Lovett all but ran up the ladder to the bridge.
C. (Sentence 2) The freighter Florentine, 320 miles northeast of the Hawaiian Island of Hilo was lumbering along at about 15 knots when a garbled message came in over the radio.
D. (Sentence 8) Steele looked back at the ship’s compass but still had nothing to say.

Question

Which sentence is missing a necessary comma after the word in bold? 
    
A. (Sentence 6) Turning away from the ship’s compass, Captain Steele looked at Lovett with narrowed eyes but made no reply.
B. (Sentence 4) With the message burned into his mind, First Mate Lovett all but ran up the ladder to the bridge.
C. (Sentence 2) The freighter Florentine, 320 miles northeast of the Hawaiian Island of Hilo was lumbering along at about 15 knots when a garbled message came in over the radio.
D. (Sentence 8) Steele looked back at the ship’s compass but still had nothing to say.

anonymous · Answer

Adding a comma before a "but" makes it a compound sentence. So sentence A, B, and D all are not necessary to have commas. However, there should most likely be one after "Hilo," in sentence 2, C. It twists the tongue when you don't pause there.