Let’s examine each part:
(A) Besides the river – This segment seems correct. "Besides" here means "next to" or "near", which fits the context.
(B) he lay – Incorrect verb usage. The verb "lay" is the past tense of "lie", and it is grammatically correct **only if** the subject is lying down without an infinitive verb to follow. However, here the sentence continues with "to take rest", which creates an awkward and incorrect structure. The better construction would be:
"he lay down" or even better: "he sat down" or "he lay down to rest".
(C) to take rest – This segment is grammatically okay in structure, although more natural phrasing would be: "to rest". However, it's not strictly incorrect.
(D) for some time – Unnatural phrasing. The phrase “for some time” is grammatically fine, but in combination with “to take rest”, it becomes a bit awkward. A smoother phrase would be: "he lay down to rest for a while" or "he rested for some time".
Corrected sentence:
"Beside the river, he lay down to rest for a while."