I need to know if A and B are CORRECT and I need HELP WITH C

Solving a)
To solve this problem, we need to remember the following property of triangles:
The sum of the internal angles of any triangle has to be equal to 180°.
In this case for the triangle in a) the sum of the internal angles is:
[tex]53+68+x[/tex]Where x is the unknown angle. This sum has to be equal to 180:
[tex]53+68+x=180[/tex]Now we need to solve for x.
• To solve for x the first step is to combine the like terms on the left side of the equation:
[tex]121+x=180[/tex]• Subtract 121 to both sides of the equation:
[tex]x=180-121[/tex]• Solve the subtraction:
[tex]x=59[/tex]Answer:
x = 59°