When solving $\frac{7}{10} \div \frac{14}{15}$, a student's first step is to cancel the 7 and 14. Why is this incorrect?

Canceling is only allowed after changing the problem to multiplication.

The student should have canceled the 10 and 15 instead.

The student should have flipped the first fraction.

Canceling is never allowed with fractions.

Which expression correctly shows the first step for solving $2\frac{1}{4} \div \frac{3}{8}$?

$\frac{9}{4} \times \frac{8}{3}$

$\frac{9}{4} \times \frac{3}{8}$

$\frac{4}{9} \times \frac{3}{8}$