Choose the correct alternative to complete the series: $a \_ n \_ b \_ \,, \, \_ n c b \_ \,, \, \_ n c b$

These questions are based on the following arrangement. Study it carefully and answer the questions.

$J ,\star, R, 3, P,L ,2 ,\# ,I,N, 7, O,C, @ ,K, 5, D, =, M, \$, 6, B, > ,A ,Q ,4$

How many such symbols are there in the above arrangement each of which is immediately followed by a consonant and immediately preceded by a number?

Which of the following will come in place of the question mark $(?)$ in the order given below?
$AE, CG, EI, GK, ?$

These questions are based on the following set of numbers.
$389 \quad 476 \quad 635 \quad 847 \quad 568$
Which number will be the smallest if the first and the last digits are interchanged in all the numbers?

Which of the following will be the middle digit of the second lowest number among the five numbers given below?
$317, 528, 439, 254, 861$

To answer these questions study carefully the following arrangement of letters, digits and symbols.

$6, =, C, E, 3, 8, G, L, M, 7, \star, @, P, R, 4, \#, \$, N, T, 5, S, V$

How many such symbols are there in the arrangement each of which is immediately preceded by a number?