<p>By the end of 1945, Alice, thirty years old but already [an expert in the field of family dynamics, had begun writing] her memoirs</p>
<p>A. [an expert in the field of family dynamics, had begun writing]
C. as an expert in the field of family dynamics, began to write</p>
<p>Why A is correct? i thought the usage of past tense is grammatically correct. There was not two actions which one come first and other later.so, I pick C. Yet, the correct answer is A.</p>