Holotype is the specimen
A) Synonym of paratype
B) Synonym of neotype
C) Synonym of lectotype
D) Used by the author of the name designated by him as the nomenclature type

Hint:A holotype is one of several kinds of name-bearing types. It comes under the International Code of Zoological Nomenclature (ICZN).

Complete answer:
Let us analyze each given option to find out the correct answer.
>Option A: Paratype is a specimen of an organism that helps define what the scientific name of a species and another taxon actually represents. It is used for the original description of a taxonomic group and specifically stated to be the one on which the original description of the taxon was based. Therefore, this is an incorrect option.
>Option B: Neotype is a specimen or illustration selected as the type when all of the material on which the name of the taxon was based is missing. So, this is not a synonym for holotype. Therefore, this is an incorrect option.
>Option C: The lectotype is a specimen or illustration designated as the type when no holotype was indicated at the time of publication. If possible, the lectotype should be selected from the syntypes or original material. Therefore, this is an incorrect option.
>Option D: Holotype is either the one specimen or illustration used by the author or designated by the author as the nomenclatural type. The single specimen designated as the type of a species by the original author at the time the species name and description were published. Therefore, this is the correct option.

Thus, the correct option is d) Used by the author of the name designated by him as the nomenclature type.

Note: It is to be noted that the type specimen is a preserved specimen. It is designated as a permanent reference for a new species, new genus, or some other taxon. They are considered permanent reference specimens.