How does BART plan to modernize its trains and infrastructure?

The correct choice highlights BART's commitment to modernizing its trains and infrastructure through a long-term capital improvement program. This program typically consists of strategic planning and investment aimed at upgrading and maintaining essential elements of the transit system.

Such a program often covers various aspects, including the replacement of aging trains, enhancement of signaling systems, and improvement of station facilities. By focusing on long-term capital investment, BART ensures that its infrastructure can meet the growing demands of riders while maintaining safety and efficiency.

The other options, while related to transit operations, do not directly address the comprehensive and systematic approach that a long-term capital improvement program entails. Increasing service frequency may improve rider experience but does not specifically pertain to infrastructure modernization. Public-private partnerships can also aid in modernization efforts, but they often work alongside capital plans rather than being a standalone solution. Reducing fares, although beneficial for accessibility, does not contribute to the necessary investment in infrastructure improvements.