A few drops of sap were collected by cutting across a plant stem by a suitable method. The sap was tested chemically. Which one of the following test results indicates that it is phloem sap?

Phloem sap is generally alkaline with pH ranging from 7.3 - 8.5 and contains high levels of K+ and Mg2+. Hence, the chemical test for alkalinity will help to identify that the exudated sap is phloem sap. So, the correct answer is 'Alkaline'.