哪類工業較合適左香港發展?

My answer is both are not suitable to be developed in HK.
This is because the rent and salaries are so high comparing to the Mainland China.
Hong Kong is focusing on the services and financial industries.
If you would like to develop something new, maybe high tech. industries is one of the possible option.

Traditionally, because there are not much natural resources, the most suitable industries would be light industries. Heavy industries locate in areas of natural resources such as coal fields which would reduce costs. For light industries, which include high technolocy industries are most suitable because they need people of high education. Proximity to outside encourage light industries for export, and that materials all over the world can transport to Hong Kong with a reduced duties than in China. Rent and salaries would soon come down as we are now suffer financial turnmoil and is very likely that the overall rental and salary level would reduce.
Hope it can be of help!