What do these two changes have in common?
a sidewalk heating up in the sun
pouring milk on oatmeal

 - Both are caused by cooling.
 - Both are chemical changes.
 - Both are caused by heating.
 - Both are only physical changes.
Step 1: Think about each change.
A sidewalk heating up in the sun is a physical change. The temperature of the sidewalk goes up, but the sidewalk is still made of the same type of matter.
Pouring milk on oatmeal is a physical change. The oatmeal and milk form a creamy mixture. But making this mixture does not form a different type of matter.
Step 2: Look at each answer choice.
Both are only physical changes.
Both changes are physical changes. No new matter is created.
Both are chemical changes.
Both changes are physical changes. They are not chemical changes.
Both are caused by heating.
A sidewalk getting warm in the sun is caused by heating. But pouring milk on oatmeal is not.
Both are caused by cooling.
Neither change is caused by cooling.