$AlCl_3$ is an electron-deficient compound,but $AlF_3$ is not. This is because

• A
  atomic size of $F$ is smaller than $Cl$,which makes $AlF_3$ more covalent
• B
  $AlCl_3$ is a covalent compound,while $AlF_3$ is an ionic compound
• C
  $AlCl_3$ exists as a dimer,but $AlF_3$ does not
• D
  $Al$ in $AlCl_3$ is in $sp^3$ hybrid state,but $Al$ in $AlF_3$ is in $sp^2$ hybrid state