Comprehension:
There are $15$ girls and some boys among the graduating students in a class. They are planning a get-together, which can be either a $1$-day event, or a $2$-day event, or a $3$-day event. There are $6$ singers in the class, $4$ of them are boys. There are $10$ dancers in the class, $4$ of them are girls. No dancer in the class is a singer.
Some students are not interested in attending the get-together. Those students who are interested in attending a $3$-day event are also interested in attending a $2$-day event; those who are interested in attending a $2$-day event are also interested in attending a $1$-day event.
The following facts are also known:
- All the girls and $80 \%$ of the boys are interested in attending a $1$-day event. $60 \%$ of the boys are interested in attending a $2$-day event.
- Some of the girls are interested in attending a $1$-day event, but not a $2$-day event; some of the other girls are interested in attending both.
- $70 \%$ of the boys who are interested in attending a $2$-day event are neither singers nor dancers. $60 \%$ of the girls who are interested in attending a $2$-day event are neither singers nor dancers.
- No girl is interested in attending a $3$-day event. All male singers and $2$ of the dancers are interested in attending a $3$-day event.
- The number of singers interested in attending a $2$-day event is one more than the number of dancers interested in attending a $2$-day event.
Which of the following can be determined from the given information?
- The number of boys who are interested in attending a $1$-day event and are neither dancers nor singers.
- The number of female dancers who are interested in attending a $1$-day event.
- Neither I nor II
- Only II
- Only I
- Both I and II