Engine room fires have been started by neg
题型：单项选择题
问题：
Engine room fires have been started by neglected oil leaks dripping on to hot pipes or exhaust manifolds （） insulation has not been replaced after maintenance.
A.which
B.when
C.whose
D.what
Engine room fires have been started by neglected oil leaks dripping on to hot pipes or exhaust manifolds （） insulation has not been replaced after maintenance.
A.which
B.when
C.whose
D.what