A. It contains a list of all references (sources of information), presented in accordance with the layout style guideline:
B. Reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose):
The lead looks clear and well written. However, how about adding a caption to the image? A simple "Sim in 2017" for example, would do. The Wikipedia Commons file should have more info.
About the part that says, Sim watched a speech by then-Prime Minister Goh Chok Tong on the social significance of clean public toilets. It feels a bit out of place in the context of his business career, unless it directly affected his decisions and career. You could consider either proving additional context as to its subsequent relevance on his career, or omitting it to streamline the narrative.
Sim founded BOP Hub, a non-profit organisation targeting bottom-of-pyramid individuals at the poorest global income margins in 2011, developing a $10,000,000 building in Ubi. I'm trying to find a relationship between the building and the rest of the sentence. With the way it's currently structured, I interpret it as BOP Hub being the entity responsible for developing the building. Is that what it means? For clarity's sake, I think it may need rephrasing.