Nh+4 is known as a

a. polyatomic ion
b. polycompound ion
c. multi-atomic ion
d. none of these

is a A. Polyatomic ion

When two atoms combine with each other through a covalent bond it leads to the formation of charged species called as polyatomic ions.  

The ammonium cation is a decidedly accused polyatomic particle of the synthetic recipe . It is shaped by the protonation of ammonia.  Ammonium is additionally a general name for decidedly charged or protonated substituted amines and quaternary ammonium cations , where at least one hydrogen molecules are supplanted by natural gatherings.