How many of the following are correct
a. increasing order of basic character $\mathrm{MgO}<\mathrm{SrO}<{\mathrm{K}}_2\mathrm{O}<{\mathrm{Cs}}_2\mathrm{O}$
b. decreasing order of covalent character $\to \mathrm{LiI}>\mathrm{LiBr}>\mathrm{LiCl}$
c. decreasing solubility in water$\to \mathrm{KI}>\mathrm{KBr}>\mathrm{KCl}$
d. decreasing order of melting point $\to \mathrm{KI}>\mathrm{NaI}>\mathrm{RbI}>\mathrm{CsI}>\mathrm{LiI}$
e. decreasing order of meting point $\to \mathrm{NaF}>\mathrm{KF}>\mathrm{LiF}>\mathrm{RbF}>\mathrm{CsF}$