Pls help dew in 10 minutes please no trolling and if you can't see the questions just comment

Which of the following of the following sets of side lengths could not form a triangle?

Solve the triangle. a = 21°, c = 105°, c = 5

This is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 5 terms.