In order to generate a crop variety with C 4 carbon fixation, a researcher expressed PEPcase enzyme from C4 pathway in leaves of the C3 plant. However, the modified C3 plant did not show carbon fixation efficiency as expected for a C4 pathway plant. The most likely reason is:

• Correct answer
  A

  Improper compartmentalisation of the C4 PEPcase in C3 leaves.
• B

  The PEPcase from C4 plant is catalytically inactive in the C3 leaves.
• C

  Carbon-dioxide fixed by C4 pathway PEPcase cannot be utilised by the RuBisCo of C3 leaves.
• D

  Overexpression of PEPcase from C4 in C3 leaves increases photorespiration.

Hence, the correct answer is option: 'A'.