Final answer:
An LTVP holder under Pass Type P1 can bring in their spouse, their unmarried children under 21 years old, and their parents if salary criteria are met.
Step-by-step explanation:
For an LTVP (Long-Term Visit Pass) holder under Pass Type P1, there are three main types of persons who may be brought into Singapore as dependents. Firstly, the spouse of the P1 pass holder can be brought in. Secondly, unmarried children under the age of 21, including legally adopted children, may be included. Thirdly, parents of the P1 pass holder can be brought in if the pass holder meets certain salary criteria set by the Ministry of Manpower.