Correct statements among regarding silicones are: ( a ) They are polymers with hydrophobic character. ( b ) They are biocompatible. ( c ) In general, they have high thermal stability and low dielectric strength. ( d ) Usually, they are resistant to oxidation and used as greases.

Step-by-step solution

Silicones with medium length chains behave as viscous oils, jellies and greases. They are chemically inert, i.e., resistant to oxidation. Since silicones are surrounded by non-polar alkyl groups, hence, are hydrophobic in nature. Being biocompatible, they are used in surgical and cosmetic implants. Hence, all options are correct.