Which one of the following elements on doping with germanium, make it a p-type semiconductor?

Step-by-step solution

The group 13 elements have 1 electron short to Ge , thus giving rise to electron deficient bond or a hole which is responsible for electrical conductivity. Thus, group 13 elements (like Ga) on dopping with Ge , make it p -type semiconductor. Here p-type specifies that conduction is through positive holes in them.