For Alex's blog post about the best places to visit in Cape Town, the most appropriate source to consult would be:
A Cape Town tourism website with detailed information about popular attractions.
This source would provide comprehensive, relevant information specifically about attractions in Cape Town, which is exactly what Alex needs for his blog post. The other options, while potentially valuable, either focus on historical significance, recent news, or personal experiences that may not give a complete view of the best places to visit.