Choose the correct statement from the following:

(a) Standard enthalpy of formation for alkali bromides becomes more negative on descending down the group.
(b) In case of  $\mathrm{CsI}$ , lattice energy is less, but  ${\mathrm{Cs}}^{+}$  is having less hydration enthalpy due to which it is less soluble in water.
(c) For alkali metal fluorides, the solubility in water increases from lithium to caesium.  $\text{LiF}$ is least soluble in water.
(d) Standard enthalpy of formation for $\text{LiF}$ is most negative among alkali metal fluorides.