In dicot stem, cambium present between the primary xylem and the primary phloem is :
A. Fascicular cambium
B. Intrafascicular cambium
C. Interfascicular cambium
D. Both A and B.

Hint: The vascular bundles present in the dicot stem are conjoint, collateral and open and are arranged in a ring. The xylem and the phloem are present on the same radius inside the conjoint vascular bundle. It is collateral because the phloem is present only on one side. It is open because cambium is present between the xylem and the phloem.

Complete answer:
To solve the given question; we must be well aware of the cambium. The cambium present primary xylem and primary phloem is known as fascicular or intrafascicular cambium.
The fascicular cambiums are called the intrafascicular cambium because they are present in between the xylem and the phloem. The fascicular cambium is the primary meristem, but after the secondary growth it changes into the secondary meristem.
The interfascicular cambium is the cambium present between two vascular bundles of the stem .When the stem is young, fascicular cambium is found in patches in a single layer between the xylem and the phloem. Later, when the plant grows these patches join together to form a complete ring.

Since, now we are well aware of the cambium, therefore the correct answer to the question is option D. i.e fascicular cambium and intrafascicular cambium.

Note: Here it must be noted that the activity of the cambium is more pronounced on the inner side as compared to the outer side. Therefore, the secondary xylem produced is more than the secondary phloem. So the cambium expands towards the outer side. Due to this growth of the secondary xylem, the primary and the secondary phloem get crushed.