解答如下:
(1)根据《高规》3.3.2条:
方案(c),高宽比,不满足。
(2)根据规程3.5.5条:
方案(b),B1=12m<0.75B=0.75×18=13.5m,不满足。
方案(a),B1=14m>0.75B=0.75×18=13.5m,满足;