It may someday be worthwhile to try to clone animal tissue for consumption, but at present, this process is prohibitively expensive.
(A) It may someday be worthwhile to try to clone animal tissue for consumption
(B) Someday, it may be worthwhile to try and clone animal tissue for consumption
(C) Trying to clone animal tissue for consumption may someday be worthwhile
(D) To try for the cloning of animal tissue for consumption may someday be worthwhile
(E) Cloning animal tissue for consumption may be worthwhile to try to do someday
Solution: The original underlined phrase is flawed as the use of "to try to clone" is awkward and it doesn't give this a definition of a process which is here mentioned as expensive to carry out.
(A) It may someday be worthwhile to try to clone animal tissue for consumption
Explanation: As explained above this is wrong.
INCORRECT(B) Someday, it may be worthwhile to try and clone animal tissue for consumption
Explanation: The use of conjunction 'and' here is wrong and it changes the intended meaning.
INCORRECT(C) Trying to clone animal tissue for consumption may someday be worthwhile
Explanation: This option is grammatically correct and maintains the intended meaning. This explains that 'Trying to clone animal tissue' is the said process which is currently expensive to perform.
CORRECT(D) To try for the cloning of animal tissue for consumption may someday be worthwhile
Explanation: Awkward prepositional usage 'for' here in 'to try for' and also wordy.
INCORRECT(E) Cloning animal tissue for consumption may be worthwhile to try to do someday
Explanation: This option is very convoluted and awkward in terms of usage of 'to try to do'.
INCORRECTOption C is the right answer.