Read the passage and answer the following question:
Raunak always used to dislike and be afraid of reptiles. Once he was trying to wear his shoes when a lizard jumped out of it. Since then he started getting scared of lizards all the more. He could not control his fear when he saw a snake in his garden. His heart started pounding, he was sweating badly, he even fainted once when someone told him that there is a lizard under his chair. The very thought of any of these reptiles, generates in him an extreme level of fear. His mother took him to a doctor, who suggested that Raunak should meet a psychotherapist.
Extreme fear that Raunak is experiencing, falls under the category of ........... disorder: