VBA code for Disable/Enable cells

In this attached excel , I have 3 types of target such as weekly , monthly , and yearly . User has to choose either one option and fill the target accordingly .

If the user is selecting target type as yearly , then monthly target cell (B3) should be disabled and user could update the target only in yearly target column.

If the user is selecting target type as monthly , then yearly target cell (B4) should be disabled and user could update the target only in monthly target column.

If the user is selecting target type as Weekly , then both Monthly target and yearly target should be disabled(B3 and B4 ).

Can someone help me to find the code for above scenario..

Please find the attached excel for your reference.