A continuous record of instances of learning by the learners is known as :

The correct option is Portfolio.

Explanation:

A portfolio is a systematic and organized collection of a student's work over a period of time. It serves as a continuous record of instances of learning, showcasing the learner's progress, effort, achievements, skills, and growth in one or more areas.

Let's briefly understand why the other options do not fit the definition:

1. Diagnostic Test: This is used at the beginning or during instruction to identify a learner's specific strengths, weaknesses, and learning gaps in a subject.

2. Continuous Comprehensive Assessment (CCE): This refers to an overall evaluation system/process that covers all aspects of student development continuously throughout the academic year, rather than being the physical record itself.

3. Proficiency Assessment: This evaluates a learner's overall ability or mastery in a specific language or subject skill at a given point in time.

Therefore, a continuous, documented record of a learner's individual learning instances and work samples is specifically known as a Portfolio.