What Does the "Axial Age" Refer To

What does the "Axial Age" refer to?

A) a period of time when people living across Eurasia radically changed how they thought about and acted toward divinity
B) another name for the Industrial Revolution when work and religion became intertwined
C) the advent of colonialism when contact between religions prompted blending, also known as syncretism
D) This is the common name for the turn of every century, which brings about rapid change and anxiety about times to come