The other bank of the stream was open ground -- a gentle slope topped with a stockade of vertical tree trunks, loopholed for rif
les, with a single embrasure through which protruded the muzzle of a brass cannon commanding the bridge. What is the meaning of the word protruded as it is used in this sentence?
A) trained or improved
B) promised or affirmed
C) enclosed or surrounded
D) pushed or thrust outward
