Define Chelate ?

Question

$\begin{array}{1 1} \text{(a)Chelate is any of a class of coordination or complex compounds consisting of a central metal atom attached to a large molecule, called a ligand, in a cyclic or ring structure.} \\ \text{(b)Chelate is any of a class of coordination or complex compounds consisting of a central metal atom attached to a smallest molecule, called a ligand, in a cyclic or ring structure.} \\ \text{(c)A chelate is a substance whose molecules can form several bonds to a single metal ion.} \\ \text{(d) None of the above}\end{array}$