(b) bottle brush
[CBSE AIPMT 2001]
Correct Option (d)
Reason : Pollination through air is known as anemophily e.g. coconut.
In Salvia, the pollination is taken place by insects (entomophily).
In Vallisneria, the pollination occurs through water (hydrophily).
In bottle brush (Callistemon) the pollination occurs through birds (ornithophily).