If an object weighs 100 N in the air and 25 N when submerged in water, what are its volume and specific weight, respectively?
a) 75 m³, 980 N/m³
b) 75 m³, 2500 N/m³
c) 100 m³, 980 N/m³
d) 100 m³, 2500 N/m³