Choose the correct statement$($s$)$ regarding the mechanism of superplasticizers

a$)$ Superplasticizers increase the workability of the concrete by increasing the water content of the mix

b$)$ Adsorption of superplasticizers to the cement particles followed by generation of repulsive forces between cement particles

c$)$ Absorption of superplasticizers to the cement particles followed by generation of attractive forces between cement particles

d$)$ Formation of superplasticizer$-$Ca $2+$ complexes and interaction with the hydration reactions

e$)$ An increase in the entrapped air content of the fresh paste leading to higher porosity and crystallinity of the hydrated cement paste