122. Data Conversion and Encoding-ii

A firmware engineer writes this debug function:

void dump(uint8_t *buf, int len) {
   for (int i = 0; i < len; i++) {
       uint8_t hi = (buf[i] >> 4) & 0x0F;
       uint8_t lo = buf[i] & 0x0F;
       putchar(hi < 10 ? '0'+hi : 'A'+hi-10);
       putchar(lo < 10 ? '0'+lo : 'A'+lo-10);
       putchar(' ');
   }
}

What does dump(data, 4) produce for data = {0xDE, 0xAD, 0xBE, 0xEF}?