The Combat Expertise feat (P119 of the CRB) says that you take a -1 on Melee Attacks AND Combat Maneuvers, to gain a +1 dodge bonus to AC: You can increase your defense at the expense of your accuracy.
What happens to Combat Maneuver DEFENSE?
b) It is also reduced by -1
c) It is increased by +1
It seems to me that (c) should be the logical choice, but the wording seems to indicate (a) ...