Select the most appropriate option to fill in the blank and make a grammatically correct sentence.

Although I had never seen her before, I ________ her from a photograph.

recognized

The most appropriate option to fill in the blank is recognized.

The sentence is in the past tense, and the verb "to recognize" needs a past tense form. The past tense form of "to recognize" is "recognized."

The other options are not grammatically correct.

• Am recognizing is the present progressive tense form of the verb "to recognize." It is not the correct tense to use in this sentence, because the speaker is talking about something that happened in the past.
• Recognize is the present tense form of the verb "to recognize." It is not the correct tense to use in this sentence, because the speaker is talking about something that happened in the past.
• Have recognized is the present perfect tense form of the verb "to recognize." It is not the correct tense to use in this sentence, because the speaker is not talking about something that happened repeatedly or over a period of time.