You are designing a financial transactions table with a clustered columnstore index in an Azure Synapse Analytics dedicated SQL pool. The table has the following columns and estimated rows per value:

• TransactionType: 40 million rows per transaction type
• CustomerSegment: 4 million rows per customer segment
• TransactionMonth: 65 million rows per month
• AccountType: 500 million rows per account type

The query requirements are:

• Analysts will most commonly filter transactions for a specific month.
• Transaction analysis will typically involve summarizing data by transaction type, customer segment, and/or account type.

You need to recommend a partitioning column for the table to minimize query times. Which column should you choose?