Answer
$1.2\,\mu F$
Work Step by Step
For the parallel connection,
$C_{p}=C_{1}+C_{2}+C_{3}$
$\implies C_{1}=C_{p}-C_{2}-C_{3}=1.7\,\mu F-0.30\,\mu F-0.20\,\mu F$
$=1.2\,\mu F$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.