The theory of organic solutes moving from 'the source to the sink' was proposed by

Answer: Option A

The theory of organic solutes moving from 'the source to the sink' was proposed by Munch.
It also known as the Pressure flow hypothesis or mass flow hypothesis, is the best-supported theory to explain the movement of sap through the phloem. It was proposed by Ernst Munch, a German plant physiologist in 1930.
The gradient of sugar from source to sink causes pressure to flow through the sieve tube toward the sink. The pressure gradient is established as a consequence of the entry of sugars in sieve elements at the source and the removal of sucrose at the sink.