Something is called a barrier to entry only if it makes entry into an industry absolutely impossible

Which of the following statements is true?

A) In the long run, the average cost curve is always downward sloping. B) In the long run, the quantities of all inputs are fixed. C) In the long run, the firm's fixed costs are greater than its variable costs. D) In the long run, all costs are variable costs. E) In the long run, the total variable cost equals the total fixed cost.

List four things that can shift the demand for an input

What will be an ideal response?