He `underline("is knowing")` the secret.

Options

A. knows
B. has been knowing
C. was knowing
D. No improvement

Answer

C

Explanation

Know' is a verb which can be used with different tense. Here, the noun 'secret' is abstract noun and suggests the action is being performed in the present from. The underlined phrase 'is knowing' is in present continous tense and does not fit here as a secret cannto be known (verb) continuoulsy. "Has been knowing" i.e., option (b) indicates present perfect tense which again does not make meaningful sense. Option (c ) "was knowing" is in past continuous form and one cannot stop knowing a secret after some time. However, option (a) 'knows' completely makes sense as it establishes the fact that the person is well aware of the secret at present and every time he will be aware of it. Thus, option (a) is the answer.