Collenchymatous hypodermis is a characteristic feature of .........

The transverse section of a plant material shows the following anatomical features under microscope $:-$
$(a)$ Collenchymatous hypodermis
$(b)$ Sclerenchymatous pericycle located just above phloem bundles in semi-lunar patches.
$(c)$ Vascular bundles are arranged in a ring.
$(d)$ Vascular bundles are conjoint & open.
Plant material should be :

Collenchymatous hypodermis is a characteristic of:

Vascular bundles in the stem of $Cucurbita$ or $Lagenaria$ are

Water cavity is found in -

Conjoint collateral closed vascular bundle is found in