State the relation between marginal cost and average variable cost.
Average Variable Cost (AVC) and Marginal Cost (MC):
When AVC declines, MC also declines at a faster rate but below the AVC curve.
When AVC increases, MC also increases at a faster rate and remains above the AVC curve.
The MC curve cuts the AVC curve from its minimum point. Also, both AVC and MC are
obtained from TVC.
AVC = `"TVC"/Q`
`MC = "ΔTC"/"ΔQ" = "ΔTVC"/"ΔQ"`