答案：C

解析：

If Alan's package weighs p pounds and costs d dollars to ship, then 6 is less than or equal to p is less than or equal to 10. Subtracting 8 across these inequalities gives the equivalent (6-8) is less than or equal to (p-8) is less than or equal to (10-8), and so (-2) is less than or equal to (p-8) is less than or equal to 2. By the definition of absolute value, it follows that (absolute value of p-8) is less than or equal to 2 must be true.