Fusion of two dissimilar gametes is called

Double fertilization is fusion of

In angiospermic fertilisation, one male gamete fuses with egg to form ...$A$... , this event is called ...$B$....

Identify $A$ and $B$ and choose the correct option

In angiosperm, triple fusion is necessary for the formation of

$A$ : More than one pollen tubes can enter an embryo sac.
$R$ : Double fertilization can occur by contribution of gametes from different pollen

The diploid and triploid product of double fertilization respectively are