How to build a multiple choice field of date ranges based on the start date and end date in a table

I have a content management app that my writers log each piece of web page content they write in. There are two tables that are related to the "Clients" table, so that we can track all of the content we write for each of our clients.

1. Content Allocations
Each record defines the type of content that the client gets each deliverable cycle (monthly) - ie- blog, informational content, social post, etc.

2. Content Deliverable Document
Each record represents a piece of content that the writer published for the client. It is related to the content Allocations. ie- blog content will be logged in the "Blog" record in the "Content Allocations" table.

Here's my issue: I need to add a multiple choice dropdown called "Deliverable Cycle" in the "Content Deliverable Documents" table. The writer would use this to select the deliverable cycle that is related to the content they logged. It would look something like this:

4/1/2021 – 4/31/2021
3/1/2021 – 3/31/2021
2/1/2021 – 2/31/2021
1/1/2021 – 1/31/2021
...

The Content Allocations (parent) table contains "Deliverable Cycle Start Date" and "Deliverable Cycle End Date"  fields. How can I create a dynamic dropdown where the writer could select the appropriate cycle date range?