I have a ___ getting to the top of the Mountain Tai A questi

在网上可以查到：have a difficulty in doing 在做某事方面有困难（in 可以省略）,不过词典中没有明确说这个是一个固定搭配.而且标注说”通常用作复数的.这个句子有个 a ,总觉得怪怪的.
词典例句：
I had considerable difficulty （in）persuading her to leave.
I had no difficulty（in）making myself understood.
我在一个外国人交流的网页上看了一下,他们说他们常用的是
① have trouble doing
② have difficulty doing
③ have a problem/ problems doing
而且这三个都表示类似的意思.（这道题好纠结啊,那个a,还有这三个差不多的单词）
他们是这样说的原句：
They both could mean the same thing,or not.If you say:He has a problem in doing something,it may mean that a.he doesn't want to do something or b.he has difficulty doing something.For example:He has a problem with going to the movies tonight because he has a lot of work to do at home.(He has questions about it; he has a mental problem about it,in other words.)
All of the following mean the same thing,too:
She has problems doing math problems.
She has a problem with math,in general.
She has problems/difficulties in math.
She has trouble doing math.
She has problems in focusing her attention on math.
There are many ways to say the same thing.
I hope I haven't confused you.
也就是说,很少在difficulty 和 trouble 前面加“a”,如果我选,我更倾向于【B】
就当作是给你提供的参考吧……好丢脸……说的不明不白的