An Astronomer Is Examining Quasars and Happens Upon Two Quasars

Multiple Choice

An astronomer is examining quasars and happens upon two quasars in nearly the same part of the sky that have identical spectra. They cannot see any massive object in the region between the two quasars. What is a reasonable explanation for this discovery?

A) The discovery is not really a surprise because all quasars are formed by the same processes and all have virtually identical spectra.
B) The two quasars are part of a binary pair of quasars that were formed together, are at the same stage in their lives, and have the same spectra.
C) The two quasars cannot be gravitational lensing images because there is no visible lensing object in the space between them.
D) The two quasars are most likely gravitational lensing images, and the lensing object is mostly dark matter with little visible emission.