Which of the following query transformations (i.e. replacing the l.h.s. expression by the r.h.s. expression) is incorrect? R₁ and R₂ are relations, C₁, C₂ are selection conditions and A₁, A₂ are attributes of R₁?

There are five records in a database.

Name	Age	Occupation	Category
Rama	27	CON	A
Abdul	22	ENG	A
Jennifer	28	DOC	B
Maya	32	SER	D
Dev	24	MUS	C

There is an index file associated with this and it contains the values 1, 3, 2, 5 and 4. Which one of the fields is the index built from?

What is the converse of the following assertion?
I stay only if you go

A die is rolled three times. The probability that exactly one odd number turns up among the three outcomes is