Which cation from the following develops the least magnetic moment?

Which of the following compounds is expected to be colourless?

Which statement is true about the transition elements?

The magnetic moment of a transition metal compound has been calculated to be $3.87 \ B.M.$ The metal ion is

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A):$ $Cu^{2+}$ in water is more stable than $Cu^{+}$.
Reason $(R):$ Enthalpy of hydration for $Cu^{2+}$ is much less than that of $Cu^{+}$.
In the light of the above statements,choose the correct answer from the options given below:

Which of the following has the highest paramagnetic character?