11. European nations fear that Russia is encroaching on Eastern European territory.
(A) fighting
(B) expanding
(C) intruding
(D) including

encroach on/upon sth
to gradually take away someone else's rights, or to take control of someone's time, work, etc.
逐步侵犯（權利）；慢慢侵佔（時間）；逐漸干擾（工作）

What the company is proposing encroaches on the rights of individuals.
公司打算做的這件事侵犯了個人的權利。

I resent it that my job is starting to encroach on my family life.
我的工作開始佔據本來屬於我家庭生活的時間，我很討厭這一點。

to gradually cover more and more of an area of land
侵蝕，蠶食（土地）

They have promised that the development will not encroach on public land.
他們已經承諾這項開發不會侵佔公共土地。

-

intrude
to go into a place or situation in which you are not wanted or not expected to be
闖入，侵擾

I didn't realize your husband was here, Dr Jones - I hope I'm not intruding.
瓊斯博士，我不知道您丈夫在這裡——但願我沒有打擾你們。

Newspaper editors are being urged not to intrude on/into the grief of the families of missing servicemen.
人們強烈要求報紙編輯不要煩擾失蹤軍人悲痛的家屬。