नदी प्रशिक्षण कार्यों (River training works) को निम्नलिखित में से किस श्रेणी में वर्गीकृत किया जा सकता है?

Which of the following river training works runs approximately parallel to the direction of the river flow?

A marginal embankment is classified as a:

In which stage of a river is river training generally not required?