ANS:B - vertically

1. Horizontally: As mentioned, horizontal installation is the most common method for laying asbestos cement pipes. It allows for the smooth flow of water or sewage through the pipes without significant impediments caused by changes in elevation or direction. Horizontal installation is practical and efficient, especially for sewer and water distribution systems running beneath roads or through urban areas. It also simplifies maintenance and repair procedures as access to the pipes is generally easier.
2. Vertically: While less common, there may be situations where asbestos cement pipes are laid vertically. Vertical installation may occur in specific applications such as drainage systems where pipes need to transport water from lower to higher elevations or from higher to lower elevations. However, vertical installation of asbestos cement pipes is not as typical as horizontal installation due to challenges related to gravity flow and potential stress on the pipes.
3. At an angle of 30° or 60°: Installing asbestos cement pipes at an angle, whether 30° or 60°, is not a common practice for standard sewer and water distribution systems. Such angles would introduce complexities in the flow dynamics within the pipes and may lead to inefficient flow patterns, increased friction losses, and potential blockages. While there might be exceptional cases where pipes need to be laid at specific angles to accommodate terrain features or engineering requirements, it's not a standard approach for laying asbestos cement pipes in typical sewer and water distribution networks.