The correct answer is: Only conclusion II follows.
The statement says that students will have the option of dropping Mathematics and Science for their school leaving certificate examination. This does not mean that students who are weak in these subjects will be admitted. It is possible that students who are strong in these subjects may choose to drop them in order to focus on other subjects. Additionally, it is possible that students who are not interested in these subjects may choose to drop them.
The statement also does not say anything about whether or not students had the choice of continuing their education without taking these subjects in the past. It is possible that they did have this choice, or it is possible that they did not.
Therefore, the only conclusion that can be drawn from the statement is that students will have the option of dropping Mathematics and Science for their school leaving certificate examination. Conclusion I cannot be drawn because the statement does not say anything about students who are weak in these subjects. Conclusion II can be drawn because the statement does say that students will have the option of dropping these subjects.