Consider this query:

INSERT INTO T1 VALUES( (SELECT x FROM T2 WHERE y = 5), (SELECT z FROM T3 WHERE q = 7 LIMIT 1) );

If the query is guaranteed to run successfully, which of the following must be true? Select all that apply.

Note that there may be other ways to guarantee it runs successfully, but do not make any assumptions about other guarantees. There may also be other guarantees needed, but only consider the options shown here.

Group of answer choices

a) x must be a key in T2

b) y must be a key in T2

c) z must be a key in T3

d) The first column in T1 must not be a key

e) The second column in T1 must not be a key