When 4 downlink streams are used, which of the following configuration schemes for PDSCH DMRS has the highest overhead?

When 4 downlink streams are used, which of the following configuration schemes for PDSCH DMRS has the highest overhead?
A . type1 preceded by a single symbol
B . type1 preceded by double symbols
C . type2 preceded by a single symbol
D . type2 preceded by double symbols

Answer: B