The evaluation of student performance in a university course is based on the weighted average of grades obtained in the disciplines by their respective number of credits, as shown in the table:
| Evaluation | Average grade (M) |
| Excellent | $9 < M \leq 10$ |
| Good | $7 \leq M \leq 9$ |
| Regular | $5 \leq M < 7$ |
| Poor | $3 \leq M < 5$ |
| Very Poor | $M < 3$ |
A certain student knows that if he obtains a ``Good'' or ``Excellent'' evaluation, he will be able to enroll in the disciplines he desires. He has already taken the exams for 4 of the 5 disciplines in which he is enrolled, but has not yet taken the exam for discipline I, as shown in the table.
| Disciplines | Grades | \begin{tabular}{ c } Number |
| of credits |
\hline I & & 12 \hline II & 8.00 & 4 \hline III & 6.00 & 8 \hline IV & 5.00 & 8 \hline V & 7.50 & 10 \hline \end{tabular}
In order to achieve his objective, the minimum grade he must obtain in discipline I is
(A) 7.00.
(B) 7.38.
(C) 7.50.
(D) 8.25.
(E) 9.00.