What is the average of the real numbers $$x$$, y and z?
I) $$2x + 3y + 4z = 29$$
II) $$5x + 4y + 3z = 25$$

A

if the statement I alone is sufficient to answer the question.

B

if the statement II alone is sufficient to answer the question.

C

if the statements I and II together are sufficient to answer the question but neither statement alone is sufficient.

D

if both the statements I and II together are not sufficient to answer the question and additional data is required.