Which letter-cluster will replace the question mark (?) to complete the given series?

PQST, TOVS, ?, BKBQ, FIEP

‘E + B’ means ‘E is the husband of B’

‘E – B’ means ‘E is the daughter of B’

‘E $ B’ means ‘E is the father of B’

‘E # B’ means ‘E is the mother of B’

If ‘N + D # Z $ B’, then how is N related to B?

In this question, three statements are given, followed by two conclusions numbered I and II. Assuming the statements to be true, even if they seem to be at variance with commonly known facts, decide which of the conclusions logically follows/follow from the statements.

Statements:

I. Some rings are fingers.

II. Some fingers are toes.

III. No toe is an earring.

Conclusions:

I. No earring is a ring.

II. Some toes are rings.

Select the option that represents the letters that, when placed from left to right in the following blanks, will complete the letter-series.

S _ U C T S R _ _ T _ R U E _ S R _ _ T