Statement A: The petiole helps directing the leaf blade towards light.

Statement B: In some leguminous plants the leaf base may become swollen, which is called the pulvinus leaf base. 

In some leguminous plants the leaf-base may become swollen, which is called the pulvinus. The petiole helps in holding the blade towards light. Long thin flexible petioles allow leaf blades to flutter in wind, thereby cooling the leaf and bringing fresh air to leaf surface.