Pronom en ou la?

Bonjour Sheila !

The correct sentence will be -> Elle en place une à l'entrée de la maison.

This is because the pronoun “en” is always used to replace a quantity.

If the sentence would have been as - 

Elle place cette/ la statue de bronze à l’entrée de la maison. 

Then, we can replace the noun by a direct object pronoun “la”. Because, here, ‘la’ is used to replace a previously mentioned object without emphasising on the quantity of the object.

Have a look at the following Kwiziq lesson demonstrating the use of “en” with quantities->

En with quantities = Of them (French Adverbial Pronouns)

Hope this helps !