Thalamus is

When a flower has both stamens and carpels,it is described as:

What is the approximate diameter of the flower of $Rafflesia$ $arnoldii$?

$A$ characteristic of angiosperms is

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$:
Assertion $A$: $A$ flower is defined as a modified shoot wherein the shoot apical meristem changes to a floral meristem.
Reason $R$: The internode of the shoot gets condensed to produce different floral appendages laterally at successive nodes instead of leaves.
In the light of the above statements,choose the correct answer from the options given below:

Which is the largest flower?