Correct option (c) 3-Phosphoglyceric acid
Explanation :
In C3 -plants the first stable product formed during dark reaction is 3-phosphoglyceric acid, Since, it is a 3 carbon compound hence, the pathway is referred as C3-pathway. Oxalo Acetic Acid (OAA) is the first stable compound in C4 -plants. It is a 4C compound.