Final answer:
The conventional cast iron soil pipe joint is made with jute fiber and poured lead. Option C) Jute; Poured is correct.
Step-by-step explanation:
While there are various fibrous materials like asbestos, which is noncombustible and has been used for multiple applications due to its reinforcing properties, the correct answer for the materials used in this specific kind of pipe joint is jute and lead.
The use of asbestos is less common now due to its health risks and regulations limiting its use.
Making a cast iron soil pipe joint traditionally involves packing jute fiber into the joint and then pouring molten lead into it to seal the pipe connection securely.
Therefore,Option C) Jute; Poured is correct.