Answer:
a. más que (>)
Step-by-step explanation:
Here is the list of first 10 numbers in spanish:

Now, From 11 to 15 they have a very unique name:

From 16 to 19 they have the following form:

So:

Now for the next multiples of 10 until 100:

Everything follow this same structure:

Except for 20 which change just a little:

Examples:

So:

Since:

The answer is:
a. más que (>)