To allocate enough space for an array of 10 integers (on a 64bit, Linux machine), I can use:malloc(64 * 10)malloc(10 * int)malloc(10 * sizeof(int))

The correct way to allocate enough space for an array of 10 integers on a 64-bit Linux machine is to use malloc(10 * sizeof(int)).

Here's why:

1. malloc(64 * 10) is incorrect because it allocates 640 bytes. This might be more than you need, or it might not be enough, depending on the size of an integer on your system. On a 64-bit system, an integer is typically 4 bytes, so you would only need 40 bytes to store 10 integers.

2. malloc(10 * int) is incorrect because int is a type, not a value. You can't multiply by a type in C.

3. malloc(10 * sizeof(int)) is correct. The sizeof operator gives you the size of a type in bytes. On a 64-bit Linux system, sizeof(int) is typically 4, so 10 * sizeof(int) gives you exactly the 40 bytes you need to store 10 integers.