Select the most appropriate option to fill in the blank. Howard tried to speak but all that came out was an __________, squeaky gargle.

inarticulate

The correct option to fill in the blank is inarticulate.

• Implausible means not likely to be true or believable. It is not the most appropriate word to use in this context, as it does not describe Howard's speech.
• Sincere means honest and genuine. It is not the most appropriate word to use in this context, as it does not describe Howard's speech.
• Easy means not difficult or challenging. It is not the most appropriate word to use in this context, as it does not describe Howard's speech.
• Inarticulate means not clear or fluent in speech. It is the most appropriate word to use in this context, as it describes Howard's speech as being unclear and difficult to understand.