Read the given statements and conclusions carefully. Assuming that the information given in the statements is ture, even if it appears to be at variance with commonly known facts, decide which of the given conclusions logically follow(s) from the statements.
Statements:
I. Some balloons are flowers.
II. All flowers are colours.
III. All colours are rainbows.
Conclusions:
(I) Some balloons are not rainbows.
(II) Some balloons are colours.

Statements:

I. Some balloons are flowers.
II. All flowers are colours.
III. All colours are rainbows.​

 (I) Some balloons are not rainbows. (False)

Since all flowers are colours, and all colours are rainbows, it logically not follows that Some balloons are not rainbows.
(II) Some balloons are colours. (True)​

Since some balloons are flowers and all flowers are colours, it implies that some balloons are colours.

Thus, correct option is (b).