[单选题]按《砌体结构工程施工规范》 GB50924-2014,3.3.15相邻施工段的砌筑高度差不得超过一个楼层的高度,也不宜大于( )m。
A.2m。
B.3m。
C.4m。
D.5m。

An abbreviation (缩写词) can be defined as a shortened form of a word or term.
Abbreviations are an attempt to communicate information fast and accurately. But this goal is not always achieved. To many people, particularly to those new to a field, reports and papers sometimes seem to be written in a telegraphic style with abbreviations so interspersed (夹杂) as to make the message almost meaningless. Owing to the lack of a comprehensive dictionary of abbreviations and the diverse definitions of abbreviations among subject areas, it is common practice in most scholarly publications to include in an appendix (目录) at the end of the book a list of the abbreviations used. Another method is to explain the abbreviation to the reader the first time it appears.
Librarians, like everyone else, tend to use abbreviations to save space and time and to eliminate the necessity of repeating words or phrases that are long and complicated. In the library and information science