Two lines intersect at point \(P\). \(\text{One}~\text{angle}\) is \(68°\), the opposite angle is \(a\), and an adjacent angle is \(b\). Identify \(\text{every}~\text{statement}\) that must be true.

A. \(a~=~68°\)
B. \(b~=~68°\)
C. \(a~+~b~=~180°\)
D. \(b~=~112°\)
E. \(a~+~68~=~180\)
F. \(b\) and the \(68°\) angle are vertical angles

Map each label’s position relative to the given angle before testing any statement. The directly opposite angle inherits the given measure through vertical-angle equality, while either adjacent angle completes a straight-angle sum with it. Use those two facts to determine the unknown relationships, then check every claim independently rather than relying on how the intersection looks.