How to respond to EDD California telephone interview to keep the unemployment benefit?

Bring a work search record. Stick to your original story. That story should be you were laid off due to lack of work or that your assignment was ended. If they ask if you would return to the employer if you had the chance say "yes". If they deny your claim and the employer says you quit, they will be asked if they would hire you back. If they say "yes" call them and ask them when you start work. If they do not give you your job back file an appeal. If they do not say they will hire you back and you lose, file an appeal and ask if they did not want you to leave and they had work available for you then why did they not want you back? Your claim will almost certainly be denied in the phone interview and they may demand you pay them back plus a fine. Do not be alarmed. File an appeal. You will win the appeal if you stick to your story.
They would ask questions concerning your employment such as your explanation for not being employed, work conditions, relationships with management and fellow employees and anything that would hinge on your being eligible for the unemployment benefits.