The correct answer is D. 51432.
The sea is calm. The calm sea is growing. The growing calm sea is the sea.
Option A, 54132, is incorrect because the word “the” is not in the correct position. The word “the” should come after the word “sea.”
Option B, 35214, is incorrect because the word “growing” is not in the correct position. The word “growing” should come after the word “calm.”
Option C, 14523, is incorrect because the word “is” is not in the correct position. The word “is” should come after the word “growing.”