Which of the following compound cannot act as a Lewis base

Lewis base : Chemical species which has capability to donate electron pair.

In ${\mathrm{NF}}_3,{\mathrm{SF}}_4, {\mathrm{ClF}}_3$ central atom ($\mathrm{i}.\mathrm{e}$ N,S, Cl) having lone pair therefore act as lewis base.

In ${\mathrm{PCl}}_5$ centrel atom (P) does not have lone pair therefore does not act as lewis base.