Some steps to rewrite the expression x3 − 16x + x2 − 16 as a product of three factors are shown below:

Step 1: x3 − 16x + x2 − 16
Step 2: x3 + x2 − 16x − 16
Step 3: x2(x + 1) − 16(x + 1)

Which of the following best shows the next two steps to rewrite the expression?

Step 4: (x2 + 16)(x + 1); Step 5: (x + 4)(x + 4)(x + 1)
Step 4: (x2 − 16)(x + 1); Step 5: (x + 4)(x + 4)(x + 1)
Step 4: (x2 − 16)(x + 1); Step 5: (x − 4)(x + 4)(x + 1)
Step 4: (x2 + 16)(x + 1); Step 5: (x − 4)(x + 4)(x + 1)