What is the fine-grained topic of the following text: Please note that Ndifuna Ukwazi (NU) is a registered Public Benefit Organisation (PBO) with S18A status in South Africa, meaning that neither you nor NU pays donations tax on donations, and that donations are deductible from your taxable income. Only return the topic.
Ndifuna Ukwazi's status as a Public Benefit Organisation in South Africa and its tax implications.