Explanation:

To determine the least value of x that makes 8x5215 divisible by 9, follow these steps:

- Divisibility Rule for 9: A number is divisible by 9 if the sum of its digits is divisible by 9.

- Find the sum of digits of 8x5215: $8+x+5+2+1+5=21+x$.

- To make $21+x$ divisible by 9, look for the smallest x.

- If $x=3$, $21+3=24$, which is not divisible by 9.

- If $x=5$, $21+5=26$, which is not divisible by 9.

- If $x=6$, $21+6=27$, which is divisible by 9.

Therefore, The correct answer is:

- Option 4: 6