What is wrong in the below Picture?

If we tell you that there is a relation between the numbers and letters in the given figure, can you analyze it and find the missing letter in the last box?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

What does a man do only once in his lifetime, but women do once a year after they are 29?

In a concert, Christina is performing a dance show with her group.
At 10:00, she and her crew were dancing in an absolutely straight line. At that time Christina was standing in 4th position from both the front and back end of the row.

What was the size of her crew?

Can you count the number of quadrilaterals in the picture below?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

Complete the table series riddle by finding the number that can replace "??".

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

The more you take me, the more you leave me behind.
Who Am I?