Boron cannot form which one of the following anions?

Which of the following statements is incorrect?

The correct orders among the following are
$A$. Atomic radius $: B < Al < Ga < In < Tl$
$B$. Electronegativity $: Al < Ga < In < Tl < B$
$C$. Density $: Tl < In < Ga < Al < B$
$D$. $1^{st}$ Ionisation Energy $: In < Al < Ga < Tl < B$
Choose the correct answer from the options given below $:$

Give the increasing order of group $13$ elements for atomic radius.

The first ionization enthalpy values (in $kJ\, mol^{-1}$) of group $13$ elements are:

Element	$B$	$Al$	$Ga$	$In$	$Tl$
Ionization Enthalpy	$801$	$577$	$579$	$558$	$589$

How would you explain this deviation from the general trend?

Boron forms $BX_3$ type of halides. The correct increasing order of Lewis-acid strength of these halides is