What is the transmission limitation on a single 1550 nm signal, at OC-192 bit-rate, over certified SMF-28 fiber using no dispersion compensation?

What is the transmission limitation on a single 1550 nm signal, at OC-192 bit-rate, over certified SMF-28 fiber using no dispersion compensation?

A.
Four-wave mixing

B.
Polarization-mode dispersion

C.
Chromatic dispersion

D.
Attenuation