下列样式定义字体间距为0.5倍间距、水平左对齐、垂直顶端对齐、有下划线正[br][/br]确的定义是:( ) A: p{text-decoration:underline. letter-spacing: 0.5em; vertical-align: top: textalign:left} B: p{texst-decoration:0.5em;letter-spacing:underline,vertical-align: top; texst-align: left} C: p{text-decoration: left: ltter-spacing: top:vertical-align: 0. 5em; text-align:underline;} D: P{text-decoration:underline; ltterspacing: 0.Sem; vertical-align: left: text-align:top;}