ANSWER:
A. red shift in the light of distant galaxies
STEP-BY-STEP EXPLANATION:
The metric expansion of space is a key piece of current science to understand the universe, through which space-time itself is described by a metric that changes over time in such a way that the spatial dimensions seem to grow or expand according to the universe gets younger or older, the evidence for this is that red shift in the light of distant galaxies.
Therefore, the correct answer is A. red shift in the light of distant galaxies
