Choose the correct alternative to complete the series: $abc....d....be....d....b...cda$

Which number would replace the question mark in the series $7, 12, 19, ?, 39$.

Which of the letters will come next in the following series?
$a, ab, abc, abcd, abcde, abcde, ?$

The following question is based on the five three-digit numbers given:
$513, 248, 371, 634, 167$
Which of the following represents the sum of all three digits of the lowest number among them?

Find out the missing letters for the given series from the given alternatives:
$abca . . . . . bcaab . . . . . ca . . . . . bbc . . . . . a$

Study carefully the following arrangement of letters, digits and symbols to answer these

questions.

$M, 7 ,\&, 8, L ,P ,@ ,Q ,N ,\beta ,T ,Y ,3 ,2 ,= ,E ,\$ ,4 ,9 ,\#, G ,H ,5$

If all the symbols are deleted from the arrangement, which of the following will be fourth to the left of the $17^{th}$ element from the left end ?