Which match type is the default match type to which all keywords are assigned?

The selection is correct because broad match is the default setting for any keyword added to a Google Ads campaign if no specific syntax (such as quotation marks for phrase match or brackets for exact match) is applied. In the context of an AI-powered strategy, broad match serves as the essential engine for reach, as it allows Google's machine learning to look beyond the literal dictionary definition of a keyword to understand the underlying user intent and related concepts. By using broad match as the default, the system can capture a wider variety of relevant, high-performing search queries—including those the advertiser may not have anticipated—while pairing with Smart Bidding to ensure that bids are only placed on auctions with a high probability of conversion. This default behavior is designed to maximize the volume of data available to the AI, enabling it to find the most efficient path to achieving the advertiser's marketing objectives across the vast and ever-changing landscape of Google Search.