Common obstacles or barriers of successful problem solving include all of the following except
a. inferring unnecessary constraints
b. ignoring irrelevant information
c. using rigid thinking that was used to solve past problems
d. perceiving items as useful for only their original function

B. Ignoring irrelevant information

Explanation:

Irrelevant infomation is any information that isn't necessary for you to solve a problem and sometimes it may take your valuable time if you focus more on this information. So if you ignore irrelevant information it is very likely that you will focus on important information and this will lead you to solving your problem probably faster. So ignoring irrelevant infomation is actual not a barrier to solving a problem but paying attention to it will be a barrier.

All of other choices are barries to successful problem solving.

- Inferring mental constraints refers to constructing mental blocks which may hinder you from actual solving the problem.

-Using rigid thinking that was used to solve past problems , focusing on past success means you can't consider other ways that may be more efficient in resolving a problem and you can't even be innovative.

-Perceiving items as useful for only their original function, this also hinders successful problem solving because it restrict your mind in thinking, such that you may have something you can use to solve your problem in your house but you won't consider it. You can't consider that you can use a plastic container that carries water as a bag if you didn't have a bag.