Simplify $[25-(-4\left)\right\{9-(6-2)\left\}\right]÷[3\times \{6+(-3)\times (-3)\left\}\right]$.

The correct option is 1.

To simplify the given numerical expression, we apply the order of operations (BODMAS/PEMDAS rule), simplifying from the innermost brackets working outward.

The given expression is:

$[25-(-4\left)\right\{9-(6-2)\left\}\right]÷[3\times \{6+(-3)\times (-3)\left\}\right]$

Step 1: Simplify the dividend (first bracket)

First, evaluate the innermost round bracket inside the first bracket:

$6-2=4$

Substitute this back into the curly braces:

$9-4=5$

Next, multiply by $-4$:

$(-4)\times 5=-20$

Now, perform the subtraction within the square bracket:

$25-(-20)=25+20=45$

Step 2: Simplify the divisor (second bracket)

First, evaluate the multiplication inside the curly braces:

$(-3)\times (-3)=9$

Next, add $6$ inside the curly braces:

$6+9=15$

Now, multiply by $3$ outside the curly braces:

$3\times 15=45$

Step 3: Perform the final division

Divide the value of the first bracket by the value of the second bracket:

$45÷45=1$

Thus, the simplified value is 1.