Excerpt from Eros Turannos
Edwin Arlington Robinson

Between a blurred sagacity
That once had power to sound him, 10
And Love, that will not let him be
The Judas that she found him,
Her pride assuages her almost,
As if it were alone the cost. --
He sees that he will not be lost, 15
And waits and looks around him.
Which dictionary definition of sound BEST applies to its use in the lines that begin stanza 2?

A) to proclaim
B) to examine, test, or investigate
C) to make a loud noise, as in an alarm
D) to test or measure the bottom of the sea