When it's bad luck to meet a black cat?

Which Number is the odd one out?

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

What has one letter and starts with an E?

I have nine bottles of wine and one of the nine bottles is poisoned.
I need to find the poisoned bottle with two facts
(1) Poison is deadly, only a sip will cost death
(2) I have two mice to do so.

How should I do it?

A sundial has the fewest moving parts of any timepiece. Which has the most?

Can you quickly find which two matchstick figures are identical?

A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

Can you replace the question mark with the correct number in the below table sequence?

I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.