Table:
|  |  | Year Ended December 31, |  |
| --- | --- | --- | --- |
|  | 2019 | 2018 | 2017 |
| Cost of revenues | 2,193 | 2,315 | 2,000 |
| Sales and marketing | 6,812 | 6,596 | 6,621 |
| Research and development | 4,804 | 6,137 | 7,949 |
| General and administrative | 18,328 | 16,338 | 15,682 |
| Total stock-based compensation expense | 32,137 | 31,386 | 32,252 |
Paragraphs:
Stock-based Compensation Expense
The following table sets forth the total stock-based compensation expense resulting from stock options, RSUs, and ESPP included in the Company’s consolidated statements of operations (in thousands):
During the years ended December 31, 2019, 2018, and 2017 the Company capitalized stock-based compensation cost of $0.5 million, $0.1 million, and $0.3 million, respectively, in projects in process as part of property and equipment, net on the accompanying consolidated balance sheets.
As of December 31, 2019, there was $60.3 million unrecognized stock-based compensation expense of which $13.9 million is related to stock options and ESPP and $46.4 million is related to RSUs. The total unrecognized stock-based compensation expense related to stock options and ESPP as of December 31, 2019 will be amortized over a weighted-average period of 2.87 years. The total unrecognized stock-based compensation expense related to RSUs as of December 31, 2019 will be amortized over a weighted-average period of 2.69 years.
Question:
How many categories are there under total stock-based compensation expense?
Answer: Objects satisfying the requirements:
Cost of revenues
sales and marketing
research and development
general and administrative
As a result, the answer is 4