What type of market research relies on interviews and focus groups?

Qualitative research is the correct choice as it is fundamentally centered on understanding people's thoughts, feelings, and motivations, which is effectively captured through interviews and focus groups. This approach emphasizes the depth of understanding rather than numerical data. Through these methods, researchers can gather rich, detailed insights into consumer attitudes and behaviors, allowing them to explore complex issues and develop deeper insights that are not easily quantifiable.

In contrast, quantitative research focuses on numerical data and statistical analysis, typically gathering data through surveys or experiments and relying on measurable variables. Descriptive research aims to provide a detailed account of characteristics, phenomena, or behaviors but does not delve into the underlying motivations or feelings of respondents as qualitative methods do. Exploratory research, while it may involve qualitative techniques, is broader and aims to formulate or define a problem and generate hypotheses rather than solely gathering in-depth insights through interviews and focus groups. Thus, qualitative research stands out as the method that utilizes interviews and focus groups to gain nuanced understanding.