The cheapest mode of transport for the conveyance of bulky goods across countries is

Step 1: Analyze the question The question asks for the cheapest way to move bulky goods (such as crude oil, coal, timber, grain, and containers) across countries, which means long distances and often international trade.

Step 2: Explain the concept The cost of transport depends on:

• Carrying capacity: how much can be moved at once
• Fuel and operating cost per tonne per kilometre
• Flexibility of route: whether the route can link different countries

Step 3: Evaluate each option

• A. Air: Very fast, but the most expensive. It has limited capacity, so it suits light, valuable, or perishable goods, not bulky ones.
• B. Land (road and rail): Moderate cost. Road has limited capacity per trip, and rail needs heavy infrastructure. Both cost more per tonne than water over long distances.
• C. Pipeline: Cheap, but only for liquids and gases such as crude oil and natural gas. It is not suitable for general bulky goods, and it is fixed to specific routes, so it rarely connects countries in general.
• D. Water (sea, ocean, and inland waterways): Ships carry enormous quantities, from thousands of tonnes in cargo vessels to hundreds of thousands in tankers and bulk carriers. The routes (seas and oceans) are natural and need no construction, so the cost per tonne per kilometre is the lowest. Water links nearly all countries and is the backbone of international trade.

Step 4: Answer Water transport is the cheapest for moving bulky goods across countries.

Correct option: D. Water

Tip: Remember the pattern "Water = Wholesale". Heavy, bulky, long-distance cargo goes by water. Air is for fast and light goods, and pipeline is for liquids and gases only. In an exam, when you see "bulky" and "cheapest," think water first.