Which of the following statements is CORRECT for
`F_(3)C-CF_2-CF_(3)`
A. All C-F bond lengths are identical
B. Two C-F bonds attached to middle C-atoms are longer compared to other C-F bond at the terminal C-atoms
C. Two C-F bonds attached to middle C-atom are shorter comparted to other C-F bond at ther terminal C-atoms
D. None is correct