Write the shortest sequence of MIPS instructions that extracts four bits, bit 18 to bit 15, from register $s1 and uses the value of this field to replace bits 12 to 9 in register $s2 without changing other bits of register $s2. Explain your method in comments.

In the context of the box model, what is the difference between a margin and a padding? a. a padding lies outside a box border, while a margin lies inside it. b. a padding lies inside a box border, while a margin lies outside it. c. a padding can be adjusted independently, while a margin depends on the size of its box. d. a padding depends on the size of its box, while a margin can be adjusted independently.