某时刻，一台PC机开始抓取数据报文，其中一个报文展开如下所示：/**************************************************************************/IP ------ IP Header --------IPIP Version = 4, header length = 20 bytesIP Type of service = 00IP000.--------- = routineIP0-------- = normal delayIP0------- = normal throughputIP0----- = normal rekiabilityIP0 -- = ECT bit - transport protocolIP0 = CE hit - no congestionIP Total length= 166 bytesIP Identificayion = 32897IP Flags= 0XIP0-------- = may fragmentIP0------ = last fragmentIP Fragment offset = 0 bytesIP Time to live= 64 seconds/hopsIP Protocol= 17 (UDP)IP Header checksum = 7A58 (correct)IP Source address= [172.16.19.1]IP Destination address = [172.16.20.70]IP No optionsIP/***************************************************************************/（1）这个报文运输层采用了什么协议？（2）该IP数据报的头部是否有选项？（3）这个报文最多经过多少个路由器就会被丢弃？（4）该IP报文的源和目的地址是什么？（5）该报文总长度是多少？是否被分段？