73. Unions-I

A developer needs to transmit a float value over UART, one byte at a time:

typedef union {
   float f;
   ___ bytes[4];
} FloatPacket;

FloatPacket pkt;
pkt.f = temperature;
for (int i = 0; i < 4; i++)
   uart_send(pkt.bytes[i]);

What type goes in the blank?