Study the words in bold and select the correct option.

As fashions in language teaching come and go, the teacher in the classroom needs reassurance that there is some bedrock beneath the shifting sands. Once solidly founded on the bedrock, like the sea anemone, the teacher can sway to the rhythms of any tides or currents, without the trauma of being swept away purposelessly.

Adapted from: Rivers, Wilga M. Communicating Naturally in a Second Language: Theory and Practice. Cambridge University Press, 1992. p. 373.