Find out the number of circles in the given picture having Illusion

During an interview, the interviewer ordered hot coffee for the candidate to relieve the stress. The coffee was kept before him. After a minute, the interviewer asked him, 'What is before you?' He replied 'Tea'.

The candidate was selected immediately. Why?

I have a head like a cat and feet like a cat, but I am not a cat. What am I?

What country can make you shiver?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

I can turn polar bears white.
I can make anyone dance.
I can make everyone cry
I can make your hands clap
I can make you thin.
I can make you smile.
I can make you smile

Can you guess the riddle?

Why do you find that most of the buildings are deprived of the 13th floor?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?