The rhyme scheme of the first 6 lines of the poem "Sick" by Shel Silverstein is ABCABC. Here option C is correct.
Each set of two lines (couplet) follows an AABB rhyme scheme, and the pattern repeats for the first six lines. In this scheme:
Line 1 (A) rhymes with Line 2 (B),
Line 3 (C) rhymes with Line 4 (A),
Line 5 (B) rhymes with Line 6 (C).
The use of rhyme in this poem contributes to its playful and whimsical tone, as Shel Silverstein describes the various ailments of the narrator in a lighthearted and humorous manner.
The rhyme scheme of the first six lines in "Sick" by Shel Silverstein is ABCABC, with a playful and whimsical tone enhancing the humorous portrayal of the narrator's imaginary illnesses. Here option C is correct.