QUESTION $1$

Consider the following redox reaction: $2$Ca$($s$)+$ O$2($g$)--->2$CaO$($s$)$

Which of the following statements about this reaction is correct?

A$.$

O$2($g$)$ is losing electrons and it is reduced

B$.$

Ca$($s$)$ is losing electrons and it is oxidised

C$.$

O$2($g$)$ is gaining electrons and it is oxidised

D$.$

Ca$($s$)$ is gaining electrons and it is reduced