Choose the sentences with the correct use of prepositions in the following options.

(A) A few of the glaciers are expected to vanish by 2050.
(B) They never turned up their proposal.
(C) It was the last report filed by the company in last month.
(D) I am indebted for you regarding help.

Choose the correct answer from the options given below :

(A) Only

The correct answer is Option (2) - (A) Only

(A) "A few of the glaciers are expected to vanish by 2050."  (Correct use of "by" to indicate a deadline)

(B) "They never turned up their proposal."  ("Turned up" is incorrect; it should be "turned down" for rejection or "brought up" for discussion.)

(C) "It was the last report filed by the company in last month."  ("In last month" is incorrect; it should be "last month" without "in.")

(D) "I am indebted for you regarding help."  ("Indebted for" is incorrect; it should be "indebted to you for your help.")