I have a situation where user based on user dropdown value selection , below control either show radio button choice or multiple select option. How to handle this kind of scenario for better user experience control level.
Does the dropdown for Option A have between 2 - 5 selections?
One advantage of radio buttons is that all choices are visible to the user.
You could use radio buttons for the first choice, then use the expose within pattern for the available subitems for Item1 and Item2.
LukeW discusses this pattern in his insightful book Web Form Design (page 186).
Here's an expose within example from Codepen, where content is exposed depending on which choice you make:
When to use either radio buttons or checklists for your subchoices.
I'm not sure if you're also asking about the subchoices, but here's a few guidelines for when to use which control.
According to the Mac OS Human Interface Guidelines
For Radio Buttons:
Radio buttons are typically presented in groups of between two and five to provide the user with a set of mutually exclusive but related choices. A radio button’s state is either on (a filled circle) or off (an empty circle).
Use a set of checkboxes when the user needs the ability to select multiple options at the same time. Except in a rare case where a mixed state is needed, radio buttons should be mutually exclusive.