A career is a long-term professional journey in a particular field or occupation that a person pursues for livelihood, growth, and personal development throughout their working life.
The source passages provided are about investment and securities, not careers — so this question cannot be grounded in them. The answer above reflects the standard CBSE/vocational curriculum definition of "career." Examiners expect a simple, one-line definition covering the key idea: a long-term pursuit of a profession/occupation. Avoid over-explaining.