Which factors influence shipping costs?

Shipping costs are influenced primarily by practical and measurable factors that directly affect logistics operations. Weight and volume are essential because they determine how much space a shipment occupies on a transport vehicle and the overall load the vehicle can carry. This consideration affects not only how many items can be shipped at once but also the type of carrier that may be needed, which can alter costs significantly.

Distance is another critical factor since shipping costs typically increase with the length of the route due to higher fuel consumption, labor costs, and wear and tear on shipping vehicles. The shipping method also plays a significant role; for instance, air freight is often quicker but much more expensive compared to ocean freight. Furthermore, fluctuating fuel prices can significantly impact shipping costs, as fuel is a substantial operational expense in logistics.

The other options don't encompass the range of factors that truly affect shipping costs. While the time of year and market demand can influence costs indirectly—such as during peak seasons when demand may raise prices—these are not the primary or fixed elements that determine shipping expenses as directly as the factors stated in the correct answer.