Vascular bundles of a dicot stem are best described as:

1. In the dicot stem xylem and phloem lie on the same radius, so the bundle is conjoint and collateral. 2. The protoxylem lies towards the centre, making the bundle endarch. 3. A cambium is present between xylem and phloem, so the bundle is open. 4. Putting these together gives conjoint, collateral, endarch and open. 5. Option B is closed (no cambium), which is the monocot stem, the trap. 6. Option C radial and exarch describes a root, not a dicot stem. 7. Option A concentric and amphivasal is also a wrong bundle type here. _Source: Samacheer Kalvi (TN SCERT) Class 10 Science, Unit 12 Plant Anatomy and Plant Physiology "Internal Structure of Dicot Stem", p.184_