The answer is definitely not 7.777777
A change in any one of the underlying factors that determine what quantity people are willing to buy at a given price will cause a shift in demand. Graphically, the new demand curve lies either to the right (an increase) or to the left (a decrease) of the original demand curve.
It is A, 60° because 180° (degree of the whole triangle) divided by the three angles is 60.
