There Are Several Conditions That Justify Limiting Imports to Ensure

There are several conditions that justify limiting imports to ensure the survival of the "infant industry" and to justify government protection. Which of the following is(are) a justification?

A) Protection allows a firm an opportunity to move down along its average cost curve over time to become competitive at world prices.
B) Protection allows a firm to reduce future costs and cause its average cost curve to shift downwards.
C) There should not be any knowledge spillovers.
D) Protection allows a firm to shift its total cost curve to the left.