Fill in the blank space for the given series with the correct alternative.
$8, 9, 8, 7, 10, 9, 6, 11, 10, (\dots), 12$

The following questions are based on the five three-digit numbers given below:
$972, 526, 487, 359, 251$
If the digits in each of the above numbers are written in reverse order,which will be the second highest number?

Which of the following will come in place of the question mark $(?)$ in the order given below?
$AC, EH, IM, MR, ?$

Choose the correct alternative to complete the series: $...acca....ccca...acccc....aaa$

Choose the correct alternative for the missing term:
$A, CD, GHI, ?, UVWXY$

How many such digits are there in the number $5231698$ each of which is as far away from the beginning of the number as when the digits are rearranged in ascending order?