Dimethyl-2-butene can be prepared by heating which of the following compounds with a strong acid?
A. (CH₃)₂C=CH−CH₂−CH₃
B. (CH₃)₂CH−CH₂−CH=CH₂
C. (CH₃)₂ CH-CH-CH=CH₂ CH₃
D. (CH₃)₃C−CH=CH₂