Virus envelope is known as
A. Core
B. Capsid
C. Virion
D. Nucleoprotein

Hint:- The name ‘virus’ means venom or poisonous fluid. Virology is the study of viruses. Viruses cause several diseases in humans, animals and plants, for example, smallpox, herpes, influenza, AIDS in humans and mosaic, leaf rolling, yellowing and curling, etc.

Complete Answer:-The general structure of the virus consists of the following parts:
Envelope- An envelope is the thin outer covering present in some viruses. It is composed of proteins from viruses and lipids and carbohydrates obtained from the host. The smaller units of the envelope are called peplomers. The envelope is mainly found in some animal viruses like the influenza virus, Rous sarcoma virus, Herpes virus, etc., some bacterial viruses and rarely in some plant viruses like potato yellow dwarf virus, etc. The viruses that lack this envelope are called naked.
Capsid- The protein coat called capsid consists of helically arranged subunits called capsomeres around the nucleic acid core. The capsomeres are small subunits that are specific in number and arrangement in different viruses. These sub-units possess antigenic properties.
Nucleoid- It is the nucleic acid present in the virus and constitutes the infective part of the virus. It utilizes the metabolic machinery of the host cell for the synthesis and assembly of viral components. It could be any one of the following types- double-stranded DNA, single-stranded DNA, double-stranded RNA or single-stranded RNA.
Enzymes- Some viruses contain certain enzymes like lysozyme in bacteriophages, reverse transcriptase in Retroviruses.
So the correct answer is 2. Capsid.

Note:- Viruses are regarded as an intermediate between non-living and living organisms. All viruses are intracellular obligate parasites and attack the specific hosts. They produce characteristic symptoms on their particular host. They also show the property of mutation.