Let A={1,2,3,4,5,6,7} and B = {1,2,3, $$\cdots$$​ 10} Then, the number of injective functions

from A to B is?

Correct option is B

Result : if |A| = n and |B| = m , then no. of injective functions from A to B are

$$P(m, n) = \frac{m!}{(m - n)!}$$​

Here , m=10 and n=7 , So no. of injective functions from A to B will be:

​$$P(m, n) = \frac{10!}{(10 - 7)!}=\frac{10!}{3!}$$ 

$$\implies \textbf{Option B is correct.}$$​​