The correct option is C The atoms lose their electrons more easily.
Across a period, the number of valence electrons increases. The groups at the left side of the table constitute metals, the right-most groups constitute non-metals and those in the middle are metalloids or semi-metals.
The metallic character reduces across a period. We know that metal oxides are basic whereas non-metal oxides are acidic in nature. Hence, the oxides become more acidic across a period.
Also, across a period, the tendency to lose electrons decreases and that to gain electrons increases.