What is defined as all changes in equity during a period excluding investments by and distributions to owners?

The correct choice focuses on the definition of comprehensive income, which encompasses all changes in equity during a specific period, excluding contributions from and distributions to owners. This means that comprehensive income includes not only the net income generated by a company's operations but also other comprehensive income items that may affect equity, such as unrealized gains and losses on certain investments or foreign currency translation adjustments.

Comprehensive income thus provides a broader perspective of a company's financial performance beyond just the traditional net income, which only reflects revenues and expenses directly related to the company's core operations. Understanding comprehensive income is essential for analyzing a company's overall health, as it reveals how different financial and non-financial factors influence equity.

Other options like market value of equity, earnings per share, and net income relate to specific aspects of an entity's finances but do not encompass the full range of changes in equity as defined by comprehensive income. Market value of equity regards the company's total market capitalization, earnings per share focuses on the profitability per share outstanding, and net income is the profit derived from operations alone, excluding various other financial impacts that comprehensive income incorporates.