As water is lost from the surface of the leaves, a negative pressure, or tension, is created. The evaporated water is replaced by water moving from inside the plant in unbroken columns that extend from the top of a plant to its roots. The same forces that create surface tension in any sample of water are responsible for the maintenance of these unbroken columns of water.T.he word "extend" is closest in meaning to which of following?
选项：

A: stretch
B: branch
C: increase
D: rotate