how does DSD silence looks like? DSD is 1bit PWM Sigma Delta audio format.In PCM that dont have dithering,silence looks like samples with 0 value,I wonder,what does DSD silence looks like.Is it just series of 0 value samples,or does it switch between 0 and 1 constantly,third option,it changes between 0 and 1,but not constantly,more in noisy random way.

Many DACs these days use are multibit sigma delta,how does multibit sigma delta silence looks like?
DSD bits are 0 and 1 indeed, but they actually represent normalized outputs of -1 and 1, respectively, since one-bit samples can only be mid-raiser-quantized. This means DSD samples cannot represent zero. One can generate DSD silence by alternating 0-s and 1-s (your second option), or by a 1-bit delta-sigma modulation of a zero PCM input, with or without dithering (your third option).
Multi-bit modulators can (and normally use) mid-tread quantization, so they can represent zero. Thus, multibit silence is either a sequence of zeroes or the output of a multi-bit delta-sigma modulator presented with a zero input.