As the paragraph states, dictator Mobuto wanted to Africanise the name of Congo but could not succeed as the new name given to the country was a Portuguese alteration. So, option (A) is correct.
Option (B) is wrong as the term Nzadi o Nzere is a local African term as per the passage.
There is no detail about any confrontation between Mobuto and Portuguese in the passage. So, options C and D are wrong.
Correct answer is $(A).$