State and explain whether the following items of income derived during the year of assessment 2018/19 are chargeable to Hong Kong profits tax:

(a) Sums received by a foreign film production company for allowing a Hong Kong television company to show in Hong Kong certain designated films it produced offshore Hong Kong. The film production company has no representative office or agent in Hong Kong.

(b) Sums representing royalty received by a foreign patent owning company under a licensing agreement with its associate company in Hong Kong. The patent was previously owned by the Hong Kong associate which subsequently sold the patent right to the foreign patent owning company. The patent was then licensed to the Hong Kong associate for its use in Hong Kong at a royalty.

(c) Profits earned by a manufacturing company from its sale of products in Hong Kong. The products were partly manufactured in Hong Kong and partly in the PRC. The manufacturing activities conducted in the PRC were greatly involved by the manufacturing company in terms of expertise, machinery, raw materials and quality control.