The unopened bud gives little clue of the colour the flower will be. If it is a wild plant, then yellow. If descended from an escaped cultivated variety, a more striking orange.
Aka Cape primrose. Streptocarpus species are popular indoor plants because they don’t need direct sunlight. The common name points to many species originating in southern Africa, and a resemblance of the leaves to those of primroses, which are not actually closely related.