@asu as you said in your first comment "in CRC we are adding 0s at the end....is this is not increasing information".
what i personally think is we are adding those bits in options field which is basically to do these kind of work mean if we have to pad something or make some modification in entire header then we have a predefined field for that. so it should not be considered additional information for that otherwise entire option field which is 40 Bytes would be considered as additional information even if it has some useful data for the one of header field in it.