The image having the complete question is attached to this answer.
Answer:
Ga
Explanation:
In order to answer this question well, we must have a good enough knowledge of the periodic table.
We know that the elements in group 3A or group 13 of the periodic table have three valence electrons in their outermost shell.
We just have to look out among the options to notice if there is any member of group 3A or 13.
Gallium is a member of this group. Hence the answer above.
