C.
What is the total mass of carbon in 33 g of ibuprofen?

              24.97 g of C

Explanation:

Molar Mass of Ibuprofen is 206.29 g/mol

Molecular Formula of Ibuprofen is C₁₃H₁₈O₂

Also, 13 C atoms has mass of 12.01 × 13 = 156.13 g

Percentage of C in Ibuprofen,

% age of C = 156.13 / 206.29 × 100 = 75.68%

Now calculate 75.68 % of 33 g as,

75.68 % = x / 33 g × 100

x = 75.68 × 33 / 100

x = 24.97 g of C

explanation:

two years ago, when picking flowers in the mountains back of yosemite valley, i found a book. it was blotted and storm-beaten; all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however; many of the inner pages were well preserved. and although all were more or less stained and torn, whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today; its granite pages have been torn and blurred by the same storms that wasted the castaway book.

two years ago, when picking flowers in the mountains back of yosemite valley; i found a book. it was blotted and storm-beaten, all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however, many of the inner pages were well preserved. and although all were more or less stained and torn; whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today, its granite pages have been torn and blurred by the same storms that wasted the castaway book.