Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

Queen Elizabeth organised a royal party.

To Avoid uninvited guest royal family set a password.
Jack (an uninvited person) plan to enter the party. He stand nearby the door.

First guest comes, the security person said 'twelve' and guest replied with six.
Second guest comes , the security person said 'six' and guest replied with 'three'.

Jack thought is enough and he walked to the entry point. The security person said 'eight' , Jack replied smilingly 'four'.
He was immediately thrown out of the party. why ?

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

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

What's a single-digit number with no value?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

A word I know has six letters it contains, remove one letter and 12 remain. What is it?

It was a dark stormy night and a couple were in a car driving madly to a city. The car broke down and the husband had to go get help from someone who spoke his language. He was afraid to leave his wife alone in the car so he locked the car before leaving. When he came back, the car was in the same state as he had left it but his wife was dead, there was blood on the floor and there was a stranger in the car. What happened?

Solve The below Equation:

ALFA + BETA + GAMA = DELTA

Living above a star, I do not burn
Eleven friends and they do not turn
I can just be visited in a sequence, not once or repeatedly
PQRS are my initials
Can you tell my name accurately?