The correct answer is C. lamp.

Here's a breakdown of the pronunciation of the underlined parts in each word:

• A. stand: The underlined "a" is pronounced as a short "a" sound, similar to the "a" in "cat."
• B. family: The underlined "a" is also pronounced as a short "a" sound.
• C. lamp: The underlined "a" is pronounced as a long "a" sound, similar to the "a" in "cake."
• D. name: The underlined "a" is pronounced as a short "a" sound.