Which organism is an obligate aerobe and facultative intracellular pathogen?

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This question hinges on recognizing a bacterium that both needs oxygen to grow and can live inside host cells. Mycobacterium tuberculosis is an obligate aerobe, so it requires oxygen for replication. It is also a facultative intracellular pathogen, meaning it can persist and multiply within macrophages while also existing outside cells under some conditions. This intracellular niche is a key part of TB’s pathogenesis, aided by its thick, waxy cell wall that helps it survive inside immune cells. The other organisms listed are not obligate aerobes and/or are not primarily intracellular pathogens: they either tolerate or do not require oxygen in the same strict way, and their typical lifestyles are not defined by intracellular replication. So the organism that fits both criteria is Mycobacterium tuberculosis.