Comprehensive ports (option D) are those which handle both bulk and general cargo in large volumes. They provide facilities for various types of cargo, including raw materials, machinery, and consumer goods, making them versatile and important for international trade.
- Ferry Ports (A) are typically used for transporting passengers and vehicles rather than bulk cargo.
- Inland Ports (B) refer to ports located inland, often on rivers or lakes, and may not always handle large volumes of cargo.
- Ports of Call (C) are ports where ships stop during a journey, but they are not necessarily focused on handling large cargo volumes.
Hence, option (D) is the correct answer.

A ladder of fixed length \( h \) is to be placed along the wall such that it is free to move along the height of the wall.
Based upon the above information, answer the following questions:
(iii) (b) If the foot of the ladder, whose length is 5 m, is being pulled towards the wall such that the rate of decrease of distance \( y \) is \( 2 \, \text{m/s} \), then at what rate is the height on the wall \( x \) increasing when the foot of the ladder is 3 m away from the wall?