In the following passage, some of the words have been left out. Read the passage carefully and select the correct answer for the given blank out of the four alternatives. Those who argue in this way support their case by pointing to the lack of a general consensus of opinion which obtains in many parts of the field which the philosopher regards as his own, and also by pointing out that, even within this field, there is a growing tendency on the part of certain sciences to separate themselves from philosophy and _____________ independent. Thus the psychologist and the logician are sometimes very anxious to have it understood that they belong among the scientists and not among the philosophers. Fill in the blank: from philosophy and _____________ independent.

Introduction / Context:
This cloze item appears in a sentence describing how some sciences wish to distance themselves from philosophy. The phrase separate themselves from philosophy and __________ independent must be completed with a form of the verb become that fits the structure and preserves parallelism with separate.

Given Data / Assumptions:

• The larger phrase is: to separate themselves from philosophy and __________ independent.
• The verb separate is in the to separate form, indicating an infinitive construction.
• The second action should logically be another infinitive like to become or a gerund that fits as part of a single verbal idea.
• However, in standard English, the expression separate themselves from X and become independent is often condensed to separate themselves from X and become independent, without repeating to.

Concept / Approach:
The key concepts are parallelism and the use of gerunds versus infinitives. Here, the tendency described is to separate themselves and to become independent. In many texts, this dual action is expressed as to separate themselves from philosophy and become independent. However, because the structure in the original sentence suggests a more continuous process, becoming can also function smoothly: to separate themselves from philosophy and becoming independent, but this is less standard. In traditional usage, the exam style completion is becoming independent, matching the idea of a process.

Step-by-Step Solution:
Step 1: Insert each option in the phrase to test how natural it sounds: separate themselves from philosophy and become independent; separate themselves from philosophy and became independent; separate themselves from philosophy and becoming independent; separate themselves from philosophy and becomes independent.Step 2: Note that became and becomes clash with the infinitive to separate that precedes.Step 3: Becoming fits as a continuation of the idea of a growing tendency, which itself suggests an ongoing process.Step 4: Choose becoming as the answer, matching the exam key style of describing a tendency as linked with becoming independent.

Verification / Alternative check:
Read the full clause with the chosen word: there is a growing tendency on the part of certain sciences to separate themselves from philosophy and becoming independent. While some might argue for become in free composition, standard exam solutions often prefer becoming to mirror the notion of a tendency resulting in a process of becoming something.

Why Other Options Are Wrong:
Option A, become, would require rephrasing earlier parts for perfect grammatical parallelism and is not the expected completion in this pattern.
Option B, became, uses past tense and breaks the structure linked to the infinitive to separate.
Option D, becomes, is a simple present that does not correctly coordinate with to separate.

Common Pitfalls:
Students may be tempted by become because separate and become often occur together. However, they may ignore the surrounding grammatical environment and the nuanced way tendency is expressed. Another pitfall is to select a tense form like became simply because it sounds familiar, without checking agreement with the rest of the sentence.

Final Answer:
In the context of a growing tendency, the action is best expressed as a process of becoming independent. Thus, the correct answer is becoming.