Select the correct statements.                

(a)  Intine of pollen grains is composed of pectocellulosic in nature

(b)  Pollen grains develop from the haploid microspore mother cells in pollen sacs of anther.

(c)  Pollen grain is diploid, unicellular, multinucleate and oval shaped structure..

(d)    Pollen grains are generally spherical measuring about 25-50 mm in diameter.

• A

  only (b) is correct

• B

  (a), (b) (c) are correct

• C

  only (a) is correct

• D

  only (d) is correct