Explanation:

The short run refers to a period in which at least one factor of production is fixed, while others are variable. In the case of the APP (Average Physical Product), it refers to the average amount of output per unit of input, and it can be calculated by dividing the total output by the total input.

The general shape of the APP in the short run is determined by the law of diminishing returns, which states that as more and more units of a variable input are added to a fixed input, the marginal product of the variable input will eventually decrease, and this will affect the average physical product.

The graph of the APP in the short run will have a U-shaped curve, and it will reach its maximum point when the marginal product is equal to zero. However, the question is asking for the general shape of the APP in the short run, which means that it can also have other shapes, depending on the specific conditions of production.

The correct answer is option 'D', which refers to the inverse U-shaped curve. This shape occurs when the marginal product of the variable input is negative, which means that adding more units of the variable input will decrease the total output. This can happen when there are too many units of the variable input relative to the fixed input, or when the variable input is of poor quality.

In summary, the general shape of the APP in the short run is determined by the law of diminishing returns, and it can be U-shaped, inverse U-shaped, or have other shapes, depending on the specific conditions of production.