(i)→(b),(ii)→(a),(iii)→(c)

(i) →(b) Thermodynamics states that the diamond will convert to graphite. Since the Gibbs free energy of graphite is less than that of the diamond.

The rate of conversion of diamond to graphite is so slow that the change is not perceptible at all.

(ii) →(a) Instantaneous means for an instant or short period of time.

Thus, the instantaneous rate is the slope concentration of reactant vs time graph i.e. - (d[R])/dt.

(iii) →(c) The average rate of a reaction is the rate of appearance or disappearance of product or reactant respectively.

The time interval is large to get the large value of change in concentration of product or a reactant.

〖Rate〗_avg=-∆R/∆T=∆P/∆T

Where ∆R is the change in the molar concentration of a reactant, ∆P is the change in the molar concentration of product and ∆T is the time interval.