Final answer:
The sailors likely chose to pray because they were in the midst of a storm that posed a significant threat to their safety, and the prayer was an act of seeking divine help in peril.
Step-by-step explanation:
Based on the context provided, it appears that the sailors chose to pray due to encountering a severe storm. This is evidenced by descriptions of daunting conditions at sea, such as the appearance of the lighthouse being a sign of near land, which they could not reach due to the storm diverting their course. The sailors also express concern about swamping and needing to scramble for the beach, indicating rough seas. Additionally, the pieces of wreckage seen by other sailors with the initials L.S. imply that the sailors' ship was indeed destroyed by the storm, as Dr. Watson also inferred. There is no mention of a religious festival, land being spotted as a positive outcome, or a sea monster which rules out options B, C, and D.