Use Of The A And An Questions Medium
The rule for using "A" or "An" before words starting with a silent "p" is to use "An." This is because the choice between "A" and "An" is determined by the sound that follows the article, not the actual letter. Since the "p" is silent and the following word begins with a vowel sound, "An" is used. For example, we say "an hour" (pronounced as "an ow-er") and "an honest person" (pronounced as "an on-est person").