Which Number is the odd one out?

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

What does the below rebus riddle means?

There is a unique number which when multiplied by any number from 1 to 6, we will get the new number that contains the same digits only.

Can you find that number?

Can you find a five letter word that is left with only two letters if one is removed?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

Only one colour, but not one size,
Stuck at the bottom, yet easily flies.
Present in sun, but not in rain,
Doing no harm, and feeling no pain.
What is it?

Buy me, smell me or deliver me, I do not change.

Who am I?

I know a 5-digit number having a property that With a 1 after it, it is three times as large as it would be with a one before it.

Guess the number?

What am I?

Can you spot what's wrong with the following sentence?

PETER WAS ANGRY AT
HIMSELF BECAUSE HE
ACCIDENTALLY LEFT THE
THE KEYS TO HIS CAR
AT HIS FRIEND'S HOUSE.