The correct answer is C. 75%, based on findings published in Deloitte's 2023 CxO Sustainability Report: Accelerating the Green Transition.

The report surveyed more than 2,000 C-suite executives across 24 countries to examine corporate sustainability priorities, climate-related business risks, investment trends, and environmental strategies.

Deloitte reported:

Some 75% said their organisations have increased their sustainability investments over the past year

Deloitte

The statistic refers specifically to the reporting period examined in Deloitte's 2023 study, rather than representing a permanent or current investment rate.

The findings demonstrate that businesses increasingly recognize environmental sustainability as a strategic investment area supporting operational resilience, resource efficiency, competitive differentiation, and long-term organizational performance.

Common investment priorities include renewable energy infrastructure, energy-efficient technologies, greenhouse gas emissions monitoring, sustainable supply chains, and circular economy initiatives.

For Cisco and its partners, these investment trends create opportunities to support customers through networking modernization, intelligent energy management, environmentally responsible infrastructure, and solutions that enable emissions reduction.

Option D, 80%, is particularly important to distinguish: Deloitte reported that 80% of executives in certain country-specific samples, including South Africa, increased sustainability investment, whereas the global figure was 75%.

Therefore, the geographical scope of the survey is essential when selecting the correct answer.