The correct order of increasing field strengths
 

Chloride ion is a strong field ligand as compared to iodide and bromide ions. 

Thiocyanate ion has more strength than fluoride and iodide ions.

Generally, ligands can be grouped in a series in the following sequence of rising field strength would be ${\mathrm{I}}^{–}<{\mathrm{Br}}^{–}<{\mathrm{SCN}}^{–}<{\mathrm{Cl}}^{–}$. 

Hence the correct answer is ${\mathrm{I}}^{–}<{\mathrm{Br}}^{–}<{\mathrm{SCN}}^{–}<{\mathrm{Cl}}^{–}$.